CBSE Questions for Class 11 Medical Chemistry Equilibrium Quiz 5 - MCQExams.com

Calculate : $${K}_{a}$$ for $$HCN$$ given $${K}_{b}({CN}^{-})=2.5\times {10}^{-5}$$
  • $$ {10}^{-5}$$
  • $$2\times {10}^{-7}$$
  • $$4\times {10}^{-10}$$
  • None of these
Assertion: The value of $${K_w}$$ increases with increase in temperature.
Reason: Water dissociates more as temperature increases.
  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
  • Assertion is true but Reason is false
  • Assertion is false but Reason is true
  • Both Assertion and Reason are false
Calculate change in concentration of $${H}^{+}$$ ion in one litre of water,when temperature changes from $$298K$$ to $$310K$$. [Given $${K}_{w}(298)={10}^{-14}, {K}_{w}(310)=2.56\times {10}^{-14}]$$.
  • $$0.3\times {10}^{-7}$$
  • $$0.6\times {10}^{-7}$$
  • $$1.2\times {10}^{-7}$$
  • $$12\times {10}^{-9}$$
What is the $$K_b$$ for $$NH_2$$ group in glycine?
  • $$4\times 10^{-3}$$
  • $$1.6\times 10^{-10}$$
  • $$6.25\times 10^{-5}$$
  • $$2.5\times 10^{-12}$$
Assertion: The buffer HCOOH/HCOONa will have pH lesser than 7.
Reason: Conjugate base of a weak acid is a strong base.
  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
  • Assertion is true but Reason is false
  • Assertion is false but Reason is true
  • Both Assertion and Reason are false
An equimolar solution of $${NaNO_2}$$ and $${HNO_2}$$ can act as a:
  • strong reductant
  • strong oxidant
  • buffer solution
  • none of these
The ionization constant of water is related to ionic product as: 
  • $${k_w>k\left [ H_2O \right ]}$$
  • $${k_w=k\left [ H_2O \right ]}$$
  • $${k_w<\left [ H_2O \right ]}$$
  • none of the above
If $${K_a}$$ for an acid, $$HA$$ is $${1\times 10^{-6}}$$, then $${K_b}$$ for $${A^{-}}$$ would be:
  • $${10^{-9}}$$
  • $${10^{-5}}$$
  • $${10^{-8}}$$
  • $${10^{-3}}$$
Sulphurous acid turns ________.
  • blue litmus into red
  • red litmus into blue
  • no change to any of the litmus paper
  • can't say
The following equilibrium is established when hydrogen chloride is dissolved in acetic acid. 

$$HCl (aq)\,+\, CH_3COOH(aq)\, \rightleftharpoons \,Cl^-(aq)\,+\,CH_3\,COOH_2(aq)$$

The set that characterizes the conjugate acid-base pairs is
  • $$(HCl,\, CH_3COOH)\, and\, (CH_3COOH_2,\, Cl^-)$$
  • $$(HCl,\, CH_3COOH_2)\, and\, (CH_3COOH,\, Cl^-)$$
  • $$(CH_2COOH_2,\, HCl)\, and\, (Cl^-,\, CH_3COOH)$$
  • $$(HCl,\, Cl^-)\, and\, (CH_3\,COO^-,\, CH_3COOH)$$
The chemical that changes its colour when it is left open in sunlight is:
  • $$FeSO_4\, (s)$$
  • $$Pb(NO_3)_2\, (s)$$
  • $$AgCl\, (s)$$
  • $$BaCl_2\, (aq)$$
_____ of acids are lower than that of bases.
  • $$log[H^+]$$
  • $$pOH$$
  • $$[H^+]$$
  • $$pH$$
Which of the following statements is correct for a solution saturated with AgCI and AgBr if their solubilities in moles per litre in separate solutions are x and y respectively?
  • $$[Ag^+]\,=\, x\,+\, y$$
  • $$[Ag^+]\,=\, [Br^-]\,+\, [Cl^-]$$
  • $$[Br^-]\,=\, y$$
  • $$[Cl^-]\,>\, x$$
Study the table carefully. Which of the above are correctly matched?

318551_2c2517925d89410f837a88e137348d8c.png
  • (i) & (iii)
  • (ii) & (iv)
  • (i), (ii) & (iii)
  • (i), (iii) & (iv)
Which of the following is correct regarding buffer solution?
  • It contains weak acid and its conjugate base.
  • It shows low change in pH on adding small amount of acid or base.
  • (A) and (B) both
  • None of these
Which of the following salts on heating gives a mixture of two gases?
  • $$Ba(NO_3)_2$$
  • $$NaNO_3$$
  • $$KNO_3$$
  • $$RbNO_3$$
0.5 mmol of $$NaCN$$ and 1 mmol of $$HCl$$ in 1 L solution is a buffer.
  • True
  • False
State whether the given statement is true or false:

$$AgCl$$ is less soluble in aqueous sodium chloride solution than in pure water.
  • True
  • False
Neutralization always produces a solution of pH=7.
  • True
  • False
When hydrated $$MgCl_2.\, 6H_2O$$ is strongly heated:
  • $$MgO$$ is formed
  • $$Mg(OH)_2$$ is formed
  • $$Mg(OH)Cl$$ is formed
  • Ahydrous $$MgCl_2$$ is formed
The dissociation constant of acetic acid at a given temperature is $$1.69\, \times\, 10^{-5}$$. The degree of dissociation of $$0.01\ M$$ acetic acid in the presence of $$0.01\ M$$ $$HCl$$ is equal to:
  • $$0.41$$
  • $$0.13$$
  • $$1.69\, \times\, 10^{-3}$$
  • $$0.013$$
What are the products formed when an aqueous solution of magnesium bicarbonate is boiled?
  • $$MgCO_3,\, H_2O,\, CO_2$$
  • $$Mg(HCO_3)_2,\, H_2O$$
  • $$Mg(OH)_2,\, H_2O$$
  • $$Mg,\, CO_2,\, H_2O$$
A mixture of aqueous solution of sodium acetate and sodium propanoate forms a buffer solution.
  • True
  • False
If we create vacuum in container $$A$$ at $$\displaystyle 25^{\circ}C$$ then:
332897_c38626fc2f6749cabc21636d4587eae9.png
  • water will be completely vaporised in the container
  • there will be no vaporisation in the container
  • the equilibrium will establish in between water vapour and liquid $$\displaystyle H_{2}O$$ and vapour pressure of water will remain same as it would be in presence of atmospheric pressure
  • the equilibrium in between $$\displaystyle H_{2}O\left ( v \right )$$ and $$ H_{2}O\left ( l \right )$$ will establish but vapour pressure of $$\displaystyle H_{2}O\left ( v \right )$$ will be more than as it would be in presence of atmospheric pressure
Which of the following can give a buffer solution?
  • $$HCI + NaOH$$
  • $$CH$$$$_3$$$$COONa$$
  • $$HCOOH + HCOONa$$
  • $$H_2SO_4 + Na_2SO_4$$

Which of the following properties of a solution of $$NaCl$$ will not vary as the concentration of salt is increased?
  • $$pH$$
  • Density
  • Refractive index
  • Electrical conductivity
Which of the following statement is correct regarding container B?
332898_c2f67646498c4e4a9dcf65bef37c570b.png
  • Water will migrate from Glass (i) to Glass (ii) and no equilibrium will establish
  • Water will migrate from Glass (i) to Glass (ii) and equilibrium will establish after some time
  • Water will not migrate to any side
  • None of these
Which of the following is/are correct when some $$HCl$$ is added to pure water? [Temperature is constant]
  • $${ K }_{ w }$$ decreases
  • Degree of dissociation of water decrease
  • At new equilibrium $$\left[ { H }^{ +} \right] _{ total }>\left[ { OH }^{ - } \right] _{ total }$$
  • Solution remains neutral
Which of the following acids has the smallest dissociation constant?
  • $$CH_3CHFCOOH$$
  • $$FCH_2CH_2COOH$$
  • $$BrCH_2CH_2COOH$$
  • $$CH_3CHBrCOOH$$
The constituent present in baking powder is:
  • Sodium benzoate
  • Acetic acid
  • Sodium lactate
  • Tartaric acid
Fill in the blanks with suitable words:

Excessive use of fertilizers makes the soil ______ so it should be treated with ______ like ________. If the soil is ____ then the organic matter should be added to it.
  • basic, acids, formic acid, acidic
  • basic, acids, milk of magnesia, neutral
  • acidic, bases, zinc carbonate, neutral
  • acidic, bases, slaked lime, basic
Which property is common between vinegar and curd?
  • Sweet taste
  • Bitter taste
  • Tasteless
  • Sour taste
A solution of ferric chloride in water is acidic to litmus due to:
  • hydrolysis
  • decomposition
  • electrolysis
  • condensation
Identify the correct option amongst the following:
Electropositive atoms tend to form :
  • negative ions
  • positive ions
  • covalent bonds
  • metallic bonds
Which one of the following substance will be most suitable for cutting a very hard material?
  • Silicon carbide
  • Lead
  • Zinc metal
  • Sodium chloride crystal
Arrange the following in order of increasing $$pH$$?
  • Water < Blood < Soda water
  • Water < Soda water < Blood
  • Soda water < Water < Blood
  • Soda water < Blood < Water
The function of 'buffer solution' is:
  • to increase the pH value in chemical reaction
  • to decrease the pH value on chemical reaction
  • to increase or decrease the pH value of according the need
  • to keep the pH value constante in chemical reaction
Which one of the following statements is true?
  • All alkalis are bases
  • Rusting is a combination of iron with oxygen dissolved in water
  • Heavy water accelerates the growth of living organisms, plants and animals
  • Sodium carbonate is used as a baking powder
If a salt after rubbing with fingers gives the smell of ammonia, then the salt is:
  • ammonium chloride
  • sodium carbonate
  • calcium carbonate
  • lead sulphide
Which of the  following methods is not used for preparing a salt?
  • Reaction between an acid and a base
  • Action of acid on metals
  • Action of acid on metal oxides
  • Dissolution of acids in water
$$pH$$ of tomato juice is 4, that means it is:
  • basic
  • acidic
  • neutral
  • none of these
The original colour of a salt is black. When it is heated its colour is changed from black to red. The salt may be:
  • zinc oxide
  • mercuric oxide
  • lead oxide
  • red lead
A solution of sodium chloride will:
  • turn red litmus blue
  • turn blue litmus red
  • turn red litmus orange
  • not change the colour of either red or blue litmus
$${ pK_b }$$ of $${ NH }_{ 3 }$$ is 4.74 and $${ pK }_{ b }$$ of $${ A }^{ - },{ B }^{ - }$$ and $${ C }^{ - }$$ are 1, 5 and 6 respectively, aqueous solution of 0.01 M has pH in the increasing order:
  • $${ NH }_{ 4 }A<{ NH }_{ 4 }B<{ NH }_{ 4 }C$$
  • $${ NH }_{ 4 }C<{ NH }_{ 4 }B<{ NH }_{ 4 }A$$
  • $${ NH }_{ 4 }C<{ NH }_{ 4 }A<{ NH }_{ 4 }B$$
  • All have equal $$pH$$
Acetic acid is used for preservation of foods.
  • True
  • False
Sea water contains about 24g of salts dissolved per litre of it.
  • True
  • False
What could be the nature of aqueous solution of sodium sulphate?
  • Acidic
  • Basic
  • Neutral
  • Nature depends on the concentration of the solution
Which of the following ions is furnished by acids in aqueous solution?
  • $$OH^-$$ ions
  • $$H^+$$ ions
  • $$H_3O^+$$ ions
  • None of these
The acid present in tea is:
  • citric
  • tannic
  • formic
  • lactic
The loss of water of crystallization to the atmosphere by a compound is termed:
  • deliquescence
  • dehydration
  • efflorescence
  • hydrolysis
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Practice Class 11 Medical Chemistry Quiz Questions and Answers