MCQ Questions for Class 11 Medical Chemistry Equilibrium Quiz 1

Which of the following is strongest conjugate base

0%
${\text{ClO}}_{\text{4}}^{\text{ - }}\,\,$
0%
${\text{HCO}}_{\text{3}}^{\text{ - }}\,\,\,$
0%
$\,\,{{\text{P}}^{\text{ - }}}\,\,$
0%
$\,{\text{HSO}}_{\text{4}}^{\text{ - }}$

Which of the following combination will act as a buffer?

0%
$NH_{3}+HCl$ (Molar ratio 1:2 )
0%
$CH_{3}COOH + NaOH$ (Molar ratio 2:1)
0%
$HCl+NaCl$ (Molar ratio 1:1)
0%
$NaOH+CH_{3}COOH$ (Molar ratio 1:1)

Number of buffers can be made by reaction of

$H_3PO_4$ and NaOH is

0%
3
0%
1
0%
4
0%
2

$HCOO^- + H_2O \rightleftharpoons HCOOH + OH^-$ is related:-

0%
$h=\sqrt{K_h}$
0%
$h=\sqrt{\frac{K_h}{C}}$
0%
$h=\sqrt{\frac{K_h}{V}}$
0%
$K_h= \sqrt{hc}$

Percentage dissociation of a

$0.024 M$ solution of a weak acid

$HA$ is:

(

${K_a}=2 \times 10^{-3}$ )

0%
$0.25 \%$
0%
$\approx 29 \%$
0%
$25 \%$
0%
$\approx 0.25 \%$

Which of the following is the correct order of hydrated radii?

0%
$Li^{+}$ < $Na^{+}$ < $K^{+}$ < $Rb^{+}$ < $Cs^{+}$
0%
$Rb^{+}$ < $Na^{+}$ < $Li^{+}$ < $Cs^{+}$ < $K^{+}$
0%
$Cs^{+}$ < $Rb^{+}$ < $K^{+}$ < $Na^{+}$ < $Li^{+}$
0%
$Li^{+}$ < $K^{+}$ < $Na^{+}$ < $Rb^{+}$ < $Cs^{+}$

For an acidic indicator has

$K_{a}$ value of

$10^{-5}$ . The

$\%$ basic form when

$pH$ equal to

$5.3$ is :

[Given

$\log 2=0.3$ ]

0%
$33.33$
0%
$66.66$
0%
$99$
0%
None of the above

When a strong base

$NaOH$ is added to the acidic buffer containing

$CH_3COOH+CH_3COONa$ then which of the following reaction occurs?

0%
$CH_3COOH+NaOH \rightarrow CH_3COONa+H_2O$
0%
$CH_3COOH+OH^-\rightarrow CH_3COO^-+H_2O$
0%
$CH_3COONa +NaOH\rightarrow CH_3COO^-+2Na^+OH^-$
0%
Both A and B

Calculate the ratio of solubility of

$AgCl$ in 0.1 M

$AgNO_3$ and in pure water.
Given :

$K_{sp} (AgCl) = 1.8 \times 10^{-10}$

0%
$1.34 \times 10^{-5} M$
0%
$1.34 \times 10^{-4} M$
0%
$2 \times 10^{-8} M$
0%
$3 \times 10^{-6} M$

What is the

$pH$ of a solution of

$0.28\ M$ acid and

$0.84\ M$ of its conjugate base if the ionztion constant of acid is

$4\times 10^{-4}$ ?

0%
$3.88$
0%
$3.34$
0%
$7$
0%
$10.12$

Which one of the following pairs will not act as a buffer?

0%
${H_2}C{O_3}$ and $N{a_2}C{O_3}$
0%
$C{H_3}COOH$ and $C{H_3}COOK$
0%
$NaCl{O_4}$ and $HCl{O_4}$
0%
$HCl{O_4}$ and $N{H_4}Cl$

Which will not be precipitated after addition of

${ ({ NH }_{ 4 }) }_{ 2 }{ CO }_{ 3 }$ in presence of

${ { NH }_{ 4 } }{ Cl }$ :-

0%
Ba
0%
Mg
0%
Ca
0%
Sr

The dissociation of water at

$25^{\circ} C$ is

$1.9\times 10^{-7}$ % and the density of water is 1gm/

$cm^{3}$ the ionization constant of water is:

0%
$3.42\times 10^{-6}$
0%
$3.42\times 10^{-8}$
0%
$1.00\times 10^{-14}$
0%
$2.00\times 10^{-16}$

$25^oC,$

$K_b$ for

$BOH=1.0\times10^{-12}.$ The concentration of hydroxyl ions in 0.01 M aqueous solution of the base would be:

0%
$1.0\times10^{-6}M$
0%
$1 \times10^{-7}M$
0%
$1.0\times10^{-5}M$
0%
$2.0\times10^{-6}M$

When some acid is added to water, the ionic product of water_________

0%
Changes with an increase in $pH$
0%
Changes with a decrease in $pH$
0%
Remains unchanged.
0%
Cannot be predicted

A solution of a salt/ salts in

$HCl$ when diluted with water turns milky. It indicates the presence of:

0%
$Sn$ salt
0%
$Bi$ salt
0%
$Sb$ salt
0%
$Cu$ salt

Explanation

$Sn, \ Bi, \ Sb$ salts turns milky when diluted with

$HCl$ .

Dissociation of

$H_3PO_3$ occurs in _______ stages.

0%
1
0%
2
0%
3
0%
4

Select the correct statement (s)

0%
All carbonate salts are soluble except carbonate salts of alkali metals and $\left ( NH_{4} \right )_{2}CO_{3}$
0%
All bicarbonate salts are soluble except $NaHCO_{3}$ which is sparingly soluble
0%
All sulphites salts are insoluble except sulphite salts of alkali metals and $\left ( NH_{4} \right )_{2}SO_{3}$
0%
All $MnO_{4} ^-$ salts are insoluble

$(A), (B)$ and

$(C)$ are:

0%
$Na_3PO_4, NaPO_3, (Mn)_3 (PO_4)_2$
0%
$Na_2HPO_4, Na_3PO_4, Mn_3 (PO_4)_2$
0%
$Na_2HPO_4, NaPO_3, Mn(PO_3)_2$
0%
$NaHPO_4, NaPO_3, NaMnPO_4$

$K_a$ value for the acid

$HA$ is

$1\times 10^{-6}$ . The value of

$K$ for

$A^- +H_3O^+ \to HA +H_2O$ is

0%
$1\times 10^{-6}$
0%
$1\times 10^{12}$
0%
$1\times 10^{-12}$
0%
$1\times 10^{6}$

The addition of

$HCl$ will not suppress the ionisation of:

0%
Acetic acid
0%
Sulphuric acid
0%
${H}_{2}S$
0%
Benzoic acid

Explanation

The addition of

$HCl$ will not suppress the ionisation of

$H_2SO_4$ because

$H_2SO_4$ is stronger acid than

$HCl$ .

Which of the following acid / base pairs act as natural buffers in living systems?

0%
$H_2CO_3 / HCO_3{^-}$
0%
${H_2PO_4} {^-} / HPO_4{^{2-}}$
0%
Histidine+ / histidine
0%
All of these

Explanation

$H_2CO_3/HCO_3^- ; H_2PO_4^-/HPO_4^{2-} ; Histidine^+ / Histidine$ all the buffers acts as natural buffers in living system.

An acidic buffer solution can be prepared by mixing the solutions of:

0%
sodium acetate and acetic acid
0%
ammonium chloride and ammonium hydroxide
0%
sulphuric acid and sodium sulphate
0%
sodium chloride and sodium hydroxide

Explanation

A solution that resists change in pH value upon the addition of a small amount of strong acid or base (less than 1 %) or when a solution is diluted is called buffer solution.

Basic buffer solution: A basic buffer solution consists of a mixture of a weak base and its salt with a strong acid. The best-known example is a mixture of

$NH_4OH$ and

$NH_4 Cl.$

Acidic buffer solution: An acidic buffer solution consists of a solution of a weak acid and its salt with a strong base. The best-known example is a mixture of a solution of acetic acid and its salt with a strong base i.e. sodium acetate.

Hence, option

$A$ is correct.

Addition of

${NH}_{4}Cl$ does not effect the

$pH$ of solution of

${NH}_{4}OH$ .

0%
True
0%
False
0%
Ambigous
0%
None

Explanation

Adding a common ion prevents the weak acid or weak base from ionizing as much as it would without the added common ion. The common ion effect suppresses the ionization of a weak acid by adding more of an ion that is a product of this equilibrium.

So addition of

${NH}_{4}Cl$ reduces dissociation of

${NH}_{4}OH$ and because of that its pH will decreases.

A compound which when dissolved in water yields hydroxyl ions as the only negative charged ions is known as:

0%
acid
0%
base
0%
alkali
0%
none of the above

Explanation

Some of the general properties of bases are as follows:-

They are bitter to taste, turn red litmus paper blue, release hydroxide ion in the solution medium.

However, not all bases have hydroxide group for eg.

$NH_3$ but alkalis are a group of water-soluble bases that have an alkali metal as a cationic part and a hydroxide ion as the anionic part.

Hence, alkalis when dissolved in water yields hydroxyl ions as the only negative charged ions. Example: NaOH

Thus, the correct answer is an option (C).

The first and second dissociation constants of an acid H

$_{2}$ A are 1.0 x 10

$^{-5}$ & 5.0 x 10

$^{-10}$ respectively. The overall dissociation constant of the acid will be:

0%
5.0 x 10 $^{-5}$
0%
5.0 x 10 $^{15}$
0%
5.0 x 10 $^{-15}$
0%
0.2 x 10 $^{5}$

Explanation

The overall dissociation constant is equal to the product of first and second dissociation constant. It is

$\displaystyle K_a = K_{a1} \times K_{a2} = 1.0 \times 10^{-5} \times 5.0 \times 10^{-10} = 5.0 \times 10^{-15}$

The minimum volume of water required to dissolve

$0.1$ g lead(II) chloride to get a saturated solution (

$K_{sp}$ of

$PbCl_2=3.2\times 10^{-8}$ ; atomic mass of Pb

$=207u$ ) is:

0%
$0.18$ L
0%
$17.98$ L
0%
$1.798$ L
0%
$0.36$ L

Explanation

$K{sp} = 3.2\times 10^{-8}$

$PbCl_2 \rightleftharpoons Pb^{2+} + 2Cl^-$

$K_{sp} = (S)(2S)^2$

$K_{sp} = 4S^3$

$s^3 = \dfrac{3.2\times 10^{-8}}{4}$

$s^3 = 8\times 10^{-9}$

$s = 2\times 10^{-3}$

$Molar\ mass\ of\ PbCl_2 = 278 g/mol$

By using Molarity formula,

$\therefore 2\times 10^{-3}=\dfrac{0.1}{{278}\times{x}}$

$\therefore x = \dfrac{0.1}{278\times 2\times 10^{-3}}$

$=\dfrac{100}{278\times 2}$

$x = 0.18L$

Which of the following salts is the most basic in aqueous solution ?

0%
$FeCl_3$
0%
$Pb(CH_3COO)_2$
0%
$Al(CN)_3$
0%
$CH_3COOK$

In some solutions, the concentration of

$H_3O^+$ remains constant even when small amounts of strong acid or strong base are added to them. These solutions are known as:

0%
colloidal solutions
0%
buffer solutions
0%
true solutions
0%
ideal solutions

Explanation

In some solutions, the concentration of

$H_3O^+$ remains constant even when small amounts of strong acid or strong base are added to them. These solutions are known as buffer solutions.

0.004 M

$\mathrm{N}\mathrm{a}_{2}\mathrm{S}\mathrm{O}_{4}$ is isotonic with 0.01 M Glucose. Degree of dissociation of

$\mathrm{N}\mathrm{a}_{2}\mathrm{S}\mathrm{O}_{4}$ is:

0%
75%
0%
50%
0%
25%
0%
85%

Explanation

Given, 0.004 M solution of

$Na_2SO_4$ is isotonic with 0.01 M solution of glucose.

Therefore, According to vant Hoff,s ideal gas equation,

$\Pi_{Na_2SO_4} = \Pi_{glucose} = MRT$

Or,

$i \times 0.004RT = 0.01RT$

$\Rightarrow i=2.5$

Now, Dissociation of

$Na_2SO_4$ is as follows:

$\begin{matrix} Na_{ 2 }SO_{ 4 } & \rightleftharpoons & 2Na^{ + } & + & SO_{ 4 }^{ 2- } \\ 1-\alpha & &2\alpha & & \alpha \end{matrix}$

So,

$i = 1-\alpha + 2\alpha+\alpha$

$i=1+2\alpha$

$\Rightarrow 2.5 = 1+2\alpha$

$\Rightarrow \alpha = 0.75$

Hence, degree of dissociation = 75%

With respect to hypochlorite, chlorate and perchlorate ions, choose the correct statement(s).

0%
The hypochlorite ion is the strongest conjugate base.
0%
The molecular shape of only chlorate ion is influenced by the lone pair of electrons of Cl.
0%
The hypochlorite and chlorate ions disproportionate to give rise to identical set of ions.
0%
The hypochlorite ion oxidizes the sulfite ion.

Explanation

(A) Since

$HOCl$ is the weakest oxyacid of chlorine. Therefore,

$ClO^-$ becomes the strongest conjugate base.

(B) Refer image,

(C)

$3ClO^-\rightarrow 2Cl+ClO^-_3;\quad K_{eq}=10^{27}$

In hot solution rate of disproportionation is fairly rapid

$4ClO_3^-\rightarrow Cl^-+3ClO_4^-;\quad K_{eq}=10^{29}$

It is thermodynamically possible but kinetically, is very slow reaction

(D) Lower oxyacids are good oxidizing agents.

$SO^{2-}_3+ClO^-\rightarrow SO^{2-}_4+Cl^-$

1987075_1950127_ans_dec38335cc9a4bbeaa63c82659258d0e.png

Aqueous solutions of

$HNO_3, KOH, CH_3COOH$ , and

$CH_3COONa$ of identical concentrations are provided. The pair(s) of solutions which form a buffer upon mixing is/ are:

0%
$HNO_3$ and $CH_3COOH$
0%
$KOH$ and $CH_3COONa$
0%
$HNO_3$ and $CH_3COONa$
0%
$CH_3COOH$ and $CH_3COONa$

Explanation

A solution that resists change in pH value upon addition of small amount of strong acid or base (less than 1 %) or when a solution is diluted is called buffer solution.

Basic buffer solution: A basic buffer solution consists of a mixture of a weak base and its salt with a strong acid. The best-known example is a mixture of

$NH_4OH$ and

$NH_4 Cl.$

So, options C and D are buffer solutions.

Which will make basic buffer?

0%
$50mL$ of $0.1$ M $NaOH+25mL$ of $0.1M\,CH_3COOH$
0%
$100mL$ of $0.1$ M $CH_3COOH+100mL$ of $0.1M\,NaOH$
0%
$100mL$ of $0.1M\,HCl+200mL$ of $0.1M\,NH_4OH$
0%
$100mL$ of $0.1M\,HCl+100mL$ of $0.1$ M\,NaOH$$

Explanation

$\begin{matrix} CH_ 3COOH+ & NaOH & \rightarrow & CH_ 3COONa+ & H\_ 2O \\ 25mL\times 0.1M=2.5mmol & \quad 50mL\times 0.1M=5mmol0 & & 0 & \\ 0 & 2.5mmol & & 2.5mmol & \end{matrix}$
This is basic solution due to

$NaOH$ . This is not basic buffer.
2)

$\begin{matrix} CH_ 3COOH+ & NaOH & \rightarrow & CH_ 3COONa+ & H_ 2O \\ 100mL\times 0.1M=10mmol & \quad 100mL\times 0.1M=10mmol & & 0 & \\ 0 & 0 & & 10mmol & \end{matrix}$
Hydrolysis of salt takes place. This is not buffer.
3)

$\begin{matrix} HCl & NH_{ 4 }OH & \rightarrow & NH_ 4Cl+ & H_ 2O \\ 100mL\times 0.1M=10mmol & \quad 200mL\times 0.1M=20mmol & & 0 & \\ 0 & 10 & & 10mmol & \end{matrix}$
This is basic buffer.
4)

$\begin{matrix} HCl & NaOH & \rightarrow & NaCl+ & H_{ 2 }O \\ 100mL\times 0.1M=10mmol & \quad 100mL\times 0.1M=20mmol & & 0 & \\ 0 & 0 & & 10mmol & \end{matrix}$
Neutral solution.

Which one of the following pairs of solution is not an acidic buffer?

0%
$H_2CO_3$ and $Na_2CO_3$
0%
$H_3PO_4$ and $Na_3PO_4$
0%
$HClO_4$ and $NaClO_4$
0%
$CH_2COOH$ and $CH_3COONa$

Explanation

An acidic buffer includes weak acid and its salt with a strong base.

$HClO_4$ and

$NaClO_4$ contains strong acid

$HClO_4$ and its salt with strong base

$NaOH$ .

$HClO_4$ and

$NaClO_4$ is not an acidic buffer.

Hence, option C is correct.

Which of the following is not a characteristic of equilibrium?

0%
Rate is equal in both directions
0%
Measurable quantities are constant at equilibrium
0%
Equilibrium occurs in reversible condition
0%
Equilibrium occurs only in open vessel at constant temperature

Explanation

Equilibrium state can only be achieved if a reversible reaction is carried out in a closed space.

So, the correct option is

$D$

$90^o C$ , pure water has

$[H^{+}]=10^{-6}M$ . The value of

$K_w$ at

$90^o C$ is __________.

0%
$10^{-6}$
0%
$10^{-8}$
0%
$10^{-12}$
0%
$10^{-14}$

Explanation

$90^o C$ , pure water has

$[H^{+}]=10^{-6}M$ .

In pure water,

$[H_3O^{+}] = [OH^{+}]$

The value of

$K_w$ at

$90^o C,$

$K_w = [H_3O^+][OH^-]=10^{-6} \times 10^{-6} =10^{-12}$

$10 \%$

$NaCl$ means :

$10$ gm of NaCl in

$100$ ml of solution

0%
True
0%
False

Explanation

$10\%$

$NaCl$ means

$10$

$gm$ of

$NaCl$ in

$100$

$ml$ of solution as

$NaCl$ is a salt and cannot be depicted in volume by volume

$\%$ .

0%
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
0%
Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
0%
Assertion is correct but Reason is incorrect
0%
Assertion is incorrect but Reason is correct

Explanation

$KW=[H^{+}] [OH^{-}]$

$[kw]=^{Mol}/_{l} \times ^{mol}/_{l}$

$=Mol^{2}L^{-2}$

The formula of hydronium ion is:

0%
$H_2O^+$
0%
$H_3O^+$
0%
$OH^-$
0%
none of the above

Explanation

Some of the general properties of acids are as follows :-

They are sour to taste.

They turn blue litmus paper red and the red litmus paper remains unaffected.

They release hydrogen ions in the solution medium and these ions combine with water to form hydronium ion.

$H^+ + H_2O \rightarrow H_3O^+$

Hence, the correct answer is option (B).

The ionic product of water is

$10^{-14}$ . What is the

$H^{+}$ ion concentration in 0.1 M NaOH solution?

0%
$10^{-14}M$
0%
$10^{-1}M$
0%
$10^{-2}M$
0%
$10^{-13}M$

Explanation

NaOH is a strong electrolyte and completely dissociates in solution.

Hence,

$[OH^-]=0.1M$ .

The ionic product of water is

$10^{-14}$ .

Hence,

$k_w=[H^+][OH^-]=10^{-14}$ or

$[H^+]=\dfrac {10^{-14}} {[OH^-]}= \dfrac {10^{-14}}{0.1}=10^{-13}M$ .

Use of a mild base like _____on the stung area gives relief.

0%
Washing soda
0%
Milk of magnesia
0%
Baking soda
0%
Calcium carbonate

The addition of NaCl to AgCl decreases the solubility of AgCl because ________.

0%
solubility product decreases
0%
solubility product remains constant
0%
solution becomes unsaturated
0%
solution becomes super saturated

Explanation

NaCl is highly soluble and when it is added to AgCl it decreases the solubility of AgCl because of common ion

$Cl^-$ and solution become super saturated.

Common salt containing small amount of sodium iodide, is called iodised salt.

0%
True
0%
False

Explanation

Physical properties of table salt or common salt:

1) When it is clear, it is white cubic crystals

2) Odourless but strong salty taste.

3) Solubility varies with Temperature

4) Hygroscopic

Generally, Table salt is not pure and contains impurities like

$MgCl_{2}$ , NaI,

$AlCl_{3}$ .

When it contains NaI it is called Iodised Salt.

Buffer Solution is prepared by mixing _________________.

0%
Weak acid and its salt of strong base
0%
Strong acid + its salt of strong base
0%
Weak acid + its salt of weak base
0%
Strong base + its salts of strong acid

Explanation

A solution that resists change in pH value upon addition of a small amount of strong acid or base (less than 1 %) or when the solution is diluted is called buffer solution.

An acidic buffer solution consists of a

$\text{solution of a weak acid and its salt with a strong base. }$ while basic buffer solution consists of a mixture of a weak base and its salt with strong acid.

If HCl is added to pure water at

$25^{0}$ C the ionic product of water will be:

0%
$> 10^{-14}$
0%
$< 10^{-14}$
0%
$10^{-14}$
0%
$> 10^{-10}$

Explanation

For ionic product of pure water:

$[H^{+}]=10^{-7}M$

$[OH^{-}]=10^{-7}M$

Product,

$K_w=10^{-14}$

lonic Product Kw of water is dependent only on temperature so it will remain same,

$K_w=10^{-14}$ .

Hence, the correct option is

$\text{C}$

The acid present in the body of red ant is ________.

0%
formic acid
0%
acetic acid
0%
nitric acid
0%
sulphuric acid

Explanation

An ant is known as Formica in Latin.

Thus the acid found in the red ant's body is known as formic acid.

Thus, we get a burning and itching sensation due to formic acid after an ant's bite.

Hence, the correct answer is an option

$(A)$ .

Alkalis when dissolved in _________ dissociates into ions.

0%
juice
0%
water
0%
kerosene
0%
liquid

Explanation

When alkalis are dissolved in water, they dissociate into cation and hydroxide ion

$(OH^-)$ .

These hydroxide ions are responsible for the basicity of the bases.

Hence, the correct answer is an option (B).

Acids are _______ in taste.

0%
sour
0%
bitter
0%
spicy
0%
sweet

$H_{3}PO_{2}$ and

$H_{4}P_{2}O_{7}$ are respectively ____.

0%
tribasic and tetrabasic acids
0%
dibasic and tetrabasic acids
0%
monobasic and tetrabasic acids
0%
tribasic and dibasic acids

Acid dissociation constant is:

0%
$pH$
0%
$pOH$
0%
$K_a$
0%
conjugate acid

Explanation

Option C is the correct answer.

Acid dissociation constant is denoted by

$K_a$ . It gives a measure of the strength of an acid in a solution.

CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 1 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 1 - MCQExams.com

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

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