MCQ Questions for Class 11 Medical Chemistry Hydrogen Quiz 1

The reaction of water with ammonia is given the following equation,

$H_2O+NH_3\rightleftharpoons NH^+_4+OH^-$ . In this reaction water behaves as :

0%
neutral
0%
base
0%
acid
0%
both acid and base

Assertion:

$H_{2}O$ is the only hydride of the chalcogens which is liquid.
Reasons:In ice, each

$O$ atom is surrounded by

$4H$ atoms.

0%
Both A and R are correct and R is the correct explanation of A
0%
Both A and R are correct but R is not the correct explanation of A
0%
A is not correct but R is correct
0%
both A and R are not correct

The photolysis of water gives the substance

0%
$OH^- + H^+$
0%
$H_2 + OH^-$
0%
$H_2 + O_2$
0%
$H_2O + H_2O_2$

Explanation

$H_2O \xrightarrow[]{\text{Photolysis}} OH^- + H^+$
Option A is correct.

Hydrogen can be put in halogen group because

0%
It has deuterium and tritium as isotopers
0%
It forms hydrides like chlorides
0%
It contains one electron only
0%
It is light

Explanation

Hydrogen forms hydrides like chlorides such as

$NaH$ and

$LiH$ .

In the reaction

$2H_2O \rightleftarrows H_3O^+ +OH^-$ , water is:

0%
A weak base
0%
A weak acid
0%
Both a weak acid and a weak base
0%
Neither an acid nor a base

Only one element of ________ forms hydride.

0%
group 6
0%
group 7
0%
group 8
0%
group 9

Explanation

The only element of group

$6$ i.e. Chromium

$(Cr)$ forms hydride. The other elements do not form hydride due to low affinity towards hydrogen.

Answer: (A) group

$6$

Sodium on reaction with cold water produces a residue. The nature of residue is:

0%
colourless, slippery and slightly cold
0%
colourful, soapy and slightly warm
0%
colourless, soapy and slightly warm
0%
colourful, slippery and slightly cold

Explanation

Sodium reacts with cold water to form

$NaOH$ . It is colourless, soapy and slightly warm.

Which of the following combination will produce

$H_{2}$ gas?

0%
$Au$ metal and $NaCN(aq)$ in the presence of air
0%
$Cu$ metal and $conc. HNO_{3}$
0%
$Fe$ metal and $conc.HNO_{3}$
0%
$Zn$ metal and $NaOH(aq)$

Explanation

Zn metal and NaOH(aq) will produce hydrogen gas.

$\displaystyle Zn +2NaOH \rightarrow Na_2ZnO_2 + H_2 \uparrow$

Gold react with sodium cyanide, oxygen and water, but no hydrogen gas is obtained.

$\displaystyle 4Au + 8NaCN + O_2 + 2H_2O \rightarrow 4Na[Au(CN)_2] + 4NaOH$

Cu metal reacts with conc. nitric acid but no hydrgen gas is obtained.

$\displaystyle Cu + 4HNO_3 \rightarrow Cu(NO_3)_2 + 2H_2O +2NO_2 \uparrow$

Fe metal reacts with conc. nitric acid but no hydrgen gas is obtained.

$\displaystyle Fe + 6HNO_3 \rightarrow Fe(NO_3)_3 + 3H_2O +3NO_2 \uparrow$

Hence, the correct option is D.

Assertion: The

$O-O$ bond length in

$H_2O_2$ is shorter than that of

$O_2F_2$ .
Reason:

$H_2O_2$ is an ionic compound.

0%
If both assertion and reason are true and the reason is a correct explanation of the assertion
0%
If both assertion and reason are true but reason is not a correct explanation of the assertion
0%
If the assertion is true but reason is false
0%
If both the assertion and reason are false
0%
If the assertion is false but the reason is true

Explanation

$H_{2}O_{2}$ is a covalent compound. In

$O_{2}F_{2}, O - O$ bond is shorter than in

$H_{2}O_{2}$ due to higher electronegativity of

$F$ .

Which of the following process is not used in the concentration of

$H_{2}O_{2}$ ?

0%
Distillation under reduced pressure
0%
Evaporation on a water bath
0%
Fractional crystallization
0%
Sublimation

Explanation

Sublimation is not involved in concentration of

$H_{2}O_{2}$ .

Concentration of Hydrogen peroxide involves the following steps:

1. Evaporation of solution to obtain

$30\%$ solution.

2. Distillation under pressure to get

$90\%$ pure solution.

3. Fractional Distillation to get

$100\%$ pure

$H_{2}O_{2}$ .

As oxygen is ______ soluble in water. Air dissolved in water contains a higher percentage of oxygen (30-35%) than ordinary air (21%).

0%
less
0%
more
0%
not
0%
none of these

Which of the following gas is lightest?

0%
Dihydrogen
0%
Helium
0%
Dinitrogen
0%
Dioxygen

Explanation

Dihydrogen

$(H_2)$ is the lightest gas as it is having two atoms of hydrogen, its molecular weight would be approximately

$2$ . And remaining atoms are having more than two I.e.,

$4, 28, 32$ for

$He, N_2, O_2$ respectively.

The boiling point of water is :

0%
$0^{\circ} C$
0%
$100^{\circ} C$
0%
$-0^{\circ} C$
0%
$-100^{\circ} C$

Explanation

The boiling point of water is

$100^{\circ}C$ .

This is because upto 100

$^{\circ}$ C water can increase it's temperature but after 100

$^{\circ}$ C it starts to change its state(i.e, from liquid to vapour) rather than to increase its temperature. Hence, the boiling point of water is 100

$^{\circ}$ C.

$H_2$ does not show litmus test. From this, we can say, that the oxide of hydrogen is _______ in nature.

0%
acidic
0%
neutral
0%
basic
0%
amphoteric

Explanation

${ H }_{ 2 }$ does not affect litmus paper as it is neutral. If it would have been acidic then it would have turn blue litmus red or if basic then vice-versa.

When water is cooled it contracts until it reaches __________ and then it starts expanding.

0%
37 $^{\circ}$ C
0%
40 $^{\circ}$ C
0%
0 $^{\circ}$ C
0%
4 $^{\circ}$ C

Explanation

Lowering of a temperature of water reduces the translation motion and thus brings the molecules closer. This is apparent in the contraction of water upon cooling. But at

$4^{ \circ }C$ , the water molecules form extensive hydrogen bonding. As a result, each water molecules is surrounded by four molecules and this increases the vacant space between the molecules. This results in expansion of the system.

option D is correct.

Water is a ______ oxide.

0%
acidic
0%
neutral
0%
basic
0%
amphoteric

Distilled water though pure, is not preferred to drink due to its flat insipid taste.

0%
True
0%
False

Explanation

There is nothing wrong with drinking distilled water (and deionised water ) other than it tastes ''flat'', this is not surprising since it is 100% pure

$H_2O$ with no minerals. Option A is correct

Concentration of

$H_{2}O_{2}$ by vacuum distillation gives hydrogen peroxide which is:

0%
about $99\%$ pure
0%
about $90\%$ pure
0%
$30\%$ pure
0%
about $50\%$ pure

Explanation

Vacuum distillation avoids decomposition of peroxide and gives crystalline

$H_2O_2$ with negligible amount of impurities.

Electronic configuration of deuterium is _________.

0%
$1s^{2}$
0%
$1s^{1}$
0%
$1s^{2}2s^{1}$
0%
$1s^{2}2s^{2}$

Explanation

Hydrogen has one proton and no neutron. Its atomic number is one and the electronic configuration is

$1s^1$ .

Deuterium has one neutron and one proton. The mass number of deuterium is

$2$ . Its electronic configuration is the same as that of hydrogen,

$1s^1$ as it is an isotope of hydrogen.

The melting point of ice on Kelvin scale is:

0%
0 K
0%
-273 K
0%
273 K
0%
373 K

A majority of farmers in India depend upon _______ for irrigating their crops.

0%
rains
0%
tube wells
0%
hand pumps
0%
canals

Pure water is neutral to litmus.

0%
True
0%
False

Which element has neither definite shape nor volume?

0%
Sodium
0%
Hydrogen
0%
Iodine
0%
Lithium

Which position for hydrogen explain all its properties?

0%
At the top of halogens
0%
At the top of alkali metals
0%
At the top of carbon family
0%
None of these

Which of the following is NOT soluble in water?

0%
Salt
0%
Sugar
0%
Oxygen
0%
Sand

Explanation

Salt is an ionic compound that is formed by a cation and anion. The ionic species have dipole-dipole attraction with water molecules and are therefore soluble.

Sugar is a polyhydroxy compounds. The hydrogen bonding between water and

$OH$ groups makes sugar soluble.

Oxygen is water soluble gas as being small molecule, gets trapped in water molecules and is utilized by water organisms for sustenance.

Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. It forms a dispersion with water and settles down with time. It is insoluble in water.

Option D is correct

Water is a kind of _____oxide.

0%
acidic
0%
basic
0%
neutral
0%
metal

Water consists of hydrogen and oxygen in the ratio of ______by volume.

0%
1:1
0%
1:2
0%
2:1
0%
3:1

Explanation

Water consists of hydrogen and oxygen in the ratio of 2:1 by volume.

$2H_{2}O + O_{2} \longrightarrow 2H_{2}O$

Change of

$H$ into

${H}^{+}$ is:

0%
oxidation of hydrogen
0%
acid base reaction
0%
reduction of hydrogen
0%
displacement reaction

Explanation

Change of

$H$ into

$H^+$ is the oxidation of hyrogen because H has zero oxidation number and

$H^+$ has +1 oxidation number,loss of electrons is oxidation.

So answer is A.

On Fahrenheit scale, the boiling point of water is:

0%
$100^{\circ}F$
0%
$80^{\circ}F$
0%
$212^{\circ}F$
0%
$32^{\circ}F$

Explanation

On the Fahrenheit scale, the freezing point of water is

$32^{\circ}F$ and the boiling point is

$212^{\circ}F$ (at standard atmospheric pressure).
Fahrenheit to Celsius :

$(F - 32) * 1.8 =C$
Boiling point of water is 100 degree C. Then,

$F = (100 * 1.8) + 32$ =

$212^{\circ}F$
Option C is correct.

The

$pH$ of water is:

0%
9
0%
3
0%
7
0%
4

The density of pure water is:

0%
0.1 g/cm $^{3}$
0%
1 g/cm $^{3}$
0%
100 g/cm $^{3}$
0%
1 kg/cm $^{3}$

Explanation

Density is the ratio of mass per unit volume.

The density of pure water is

$1 g / cm^{3}$ or

$1000 kg / m^{3}$ .

Pure water is a ______ conductor of electricity.

0%
good
0%
bad
0%
semi
0%
none of these

What is the molecular weight of water?

0%
21
0%
18
0%
20
0%
16

Explanation

The atomic masses of O and H are 16 g/mol and 1 g/mol respectively.
The molecular formula of water is

$H_2O$ and its molecular weight

$2(1) + 16=18$ g/mol.
Note:
Water is one of the most precious resources on earth and is necessary for all living beings. We use water for different purposes like drinking, cooking, bathing, washing and many more activities. Pure water is colorless, odorless and tasteless.

Aquatic animals use ______ dissolved in water to respire.

0%
$\displaystyle { CO }_{ 2 }$
0%
$\displaystyle { H }_{ 2 }$
0%
$\displaystyle { O }_{ 2 }$
0%
$\displaystyle { H }_{ 2 }{ O }_{ 2 }$

Water is formed by the hydrogen and oxygen combined in the ratio

$1 : 9$ by weight.

0%
True
0%
False

Explanation

$2H_2+O_2\rightarrow 2H_2O$

$4:64$

Hydrogen and oxygen combine in the ratio of

$1:8$ ratio by weight.

Which one of the following is not a physical property of water?

0%
Water has low specific heat capacity
0%
It expands on cooling
0%
It is odorless and tasteless
0%
The boiling point of water is $100^\circ C$

The chemical formula of ice is:

0%
O $_2$
0%
H $_2$ O
0%
N $_2$
0%
H $_2$

Explanation

The chemical formula of ice is $H_2O$ , as ice constitutes only water molecules which are solidified. Hence even ice chemical formula is same as water.

The boiling point of water is inversely proportional to the atmospheric pressure.

0%
True
0%
False

Pure water has a pleasant taste.

0%
True
0%
False

The density of water is:

0%
$1\ g/cm$ $^3$
0%
$20\ g/cm$ $^3$
0%
$2\ g/cm$ $^3$
0%
$0.1\ g/cm$ $^3$

Explanation

The density of water is

$1 g/cm^{3}$ . Density is a ratio of Mass to the Volume. 1 meter long, 1 meter wide, 1 meter high storage tank can store 1,000 kg mass of water. So the density of water is 1. Therefore 1 kg water= 1 litre water(approximately).

Hydrogen is a non-metal having __________electron in the valence shell.

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

Explanation

Hydrogen is a non-metal having

${ 1e }^{ - }$ in its outer most shell (valence shell).

Which one of the following property is high in the case of water?

0%
Surface tension
0%
Specific heat
0%
Heat of vaporization and heat of fusion
0%
All of the above

Hydrogen exhibits:

0%
electropositive character
0%
elctronegative character
0%
Both A and B
0%
None of the above

Which symbol is used for the element hydrogen?

0%
$Hg$
0%
$He$
0%
$H$
0%
$Ho$
0%
$Hf$

Explanation

Hyrogen is represented as

$H$

Water

$\left({H}_{2}O\right)$ is liquid while all other molecules of equivalent and even higher molecular weight are present in gaseous state because of

0%
Covalent bonding between Hydrogen and Oxygen.
0%
Electrostatic attraction among water molecules.
0%
Hydrogen bonds.
0%
Ionic bonds.

Explanation

$H_2O$ there is hydrogen bonding because oxygen has a high electronegativity(only second to flourine). so, the hydrogen atoms from other molecules of water forms a hydrogen bonds with oxygen resulting in intermolecular hydrogen bonding, which results liquid form of water.

According to recent views, which is the current representation of hydrated proton in aqueous solution?

0%
$H^{+}$
0%
$H_{9}O_{5}^{+}$
0%
$H_{9}O_{4}^{+}$
0%
$H_{3}O^+$

Explanation

The hydrated proton is represented as

$H_3O^+$ . Hence, the correct option is

$D$ .

Among the hydrides given below which are reasonably good acid?

0%
$NH_{3}$
0%
$HF$
0%
$HN_{3}$
0%
$NaH$

Explanation

The

$pK_a$ values of the given compounds are:

$HN_3$ : 4.6

$HF$ : 3.17

$NH_3$ : 38

$NaH$ : 35

Higher the

$pK_a$ lower will be the acidic strength. Since the

$pK_a$ of

$NH_3$ and

$NaH$ are too high, they are basic in nature. Therefore, among the given compounds

$HF$ and

$HN_3$ are acidic and

$HF$ is more acidic.
Option B is correct.

The hydride ion,

$H^{-}$ is a stronger base than its hydroxide ion

$OH^{-}$ . Which of the following reactions will occur, if sodium hydride

$(NaH)$ is dissolved in water?

0%
$H^{-}{\left ( aq \right )}+H_{2}O\rightarrow H_{2}O$
0%
$H^{-}{\left ( aq \right )}+H_{2}O{\left ( l \right )}\rightarrow OH^{-}+H_{2}$
0%
$H^{-}+H_{2}O\ \rightarrow\ No\ reaction$
0%
$None\ of\ the\ above$

Explanation

Sodium hydride

$(NaH)$ react with water to form hydrogen gas and the sodium hydroxide

$(NaOH)$ .

$NaH+H_2O\rightarrow H_2+NaOH$
i.e.,

$Na^+, H^-$ and

$H^+, OH^-$ give rise to

$H_2$ and

$NaOH$ . So, it is similar to option B.

In which of the following reaction, dihydrogen acts as an oxidising agent?

0%
$Ca+H_{2}\rightarrow$
0%
$H_{2}+O_{2}\rightarrow$
0%
$H_{2}+F_{2}\rightarrow$
0%
$CuO+H_{2}\rightarrow$

Explanation

As the calcium is having

$2$ electrons more

$(1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 4s^2)$ than the inert gas configuration, so it can give its two electrons to two hydrogens leading to the formation of

$CaH_2$ and cause oxidation in

$Ca$ .

$Ca+H_2\rightarrow CaH_2$

Here, hydrogen is acting as the oxidising agent.

$2$ g of

$Al$ is treated separately with an excess of dil.

$H_{2}SO_{4}$ and excess of

$NaOH$ . The ratio of the volume of hydrogen evolved is :

0%
$2:3$
0%
$1:1$
0%
$2:1$
0%
$1:2$

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

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

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

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Practice Class 11 Medical Chemistry Quiz Questions and Answers

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