Hydrogen MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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61.
Given below are the two reactions of $${H_2}{O_2}.$$ Mark the correct statement which follows.
$$\left( {\text{i}} \right)2KMn{O_4} + 3{H_2}S{O_4} + 5{H_2}{O_2}$$ $$ \to {K_2}S{O_4} + 2MnS{O_4} + 8{H_2}O + 5{O_2}$$
$$\left( {{\text{ii}}} \right)2Cr{\left( {OH} \right)_3} + 4NaOH + 3{H_2}{O_2}$$ $$ \to 2N{a_2}Cr{O_4} + 8{H_2}O$$
A
(i) Shows oxidising nature of $${H_2}{O_2}$$ and (ii) shows reducing nature of $${H_2}{O_2}.$$
B
In (i) $${H_2}{O_2}$$ acts as a reducing agent and in (ii) it acts as an oxidising agent.
C
In both (i) and (ii), $${H_2}{O_2}$$ acts as an oxidising agent.
D
In both (i) and (ii), $${H_2}{O_2}$$ acts as a reducing agent.
Answer :
In (i) $${H_2}{O_2}$$ acts as a reducing agent and in (ii) it acts as an oxidising agent.
In (i) $${H_2}{O_2}$$ reduces $$KMn{O_4}$$ to $$MnS{O_4}$$ and is oxidised to $${O_2}.$$
In (ii) $${H_2}{O_2}$$ oxidises $$Cr{\left( {OH} \right)_3}$$ to $$N{a_2}Cr{O_4}$$ and is reduced to $${H_2}O.$$
62.
Liquid water is denser than ice due to
A
higher surface tension
B
hydrogen bonding
C
van der Waals forces
D
covalent bonding
Answer :
hydrogen bonding
Due to extensive $$H$$ - bonding water is denser than ice. Some of the $$H$$ - bonding breaks when ice is formed.
63.
The oxidation states of most electronegative element in the products of reaction $$Ba{O_2}$$ with $$dil.\,{H_2}S{O_4}$$ are
A
0 and – 1
B
–1 and – 2
C
– 2 and 0
D
– 2 and + 1
Answer :
–1 and – 2
$$Ba{O_2} + {H_2}S{O_4} \to BaS{O_4} + {H_2}{O_2}.$$
oxygen has common $$O.S.$$ as $$-2$$ and in peroxides as $$–1.$$
64.
Which of the following reactions shows reduction of water?
A
$$2{H_2}O + Mg \to Mg{\left( {OH} \right)_2} + {H_2}$$
Water is reduced to dihydrogen by highly electropositive metals. In this reaction $${H_2}O$$ is reduced to $${H_2}.$$ In other two reactions, $${H_2}O$$ is oxidised to $${O_2}$$ and $${P_4}{O_{10}}$$ is hydrolysed by water.
65.
Which of the following metal evolves hydrogen on reaction with cold dilute $$HN{O_3}?$$
66.
A metal which does not react with cold water but reacts with steam to liberate $${H_2}$$ gas is
A
$$Na$$
B
$$Mg$$
C
$$Au$$
D
$$Fe$$
Answer :
$$Fe$$
$$Na$$ reacts with cold water, $$Mg$$ reacts with hot water, $$Fe$$ reacts with steam and $$Au$$ does not react with water.
$$3Fe + \mathop {4{H_2}O}\limits_{\left( {{\text{steam}}} \right)} \to F{e_3}{O_4} + 4{H_2} \uparrow $$
67.
Which is not a property of water?
A
It is a colourless and tasteless liquid.
B
There is no hydrogen bonding in solid state of water.
C
It is an excellent solvent for transportation of ions in plants and animals.
D
Ice is lighter than liquid water.
Answer :
There is no hydrogen bonding in solid state of water.
There is extensive hydrogen bonding in solid state of water.
68.
Which of the following metals does not liberate hydrogen from acids?
A
$$Fe$$
B
$$Cu$$
C
$$Mg$$
D
$$Zn$$
Answer :
$$Cu$$
Copper being less reactive than hydrogen cannot displace hydrogen from acids.
69.
What will be the mass of oxygen liberated by decomposition of 200$$\,mL$$ hydrogen peroxide solution with a strength of 34$$\,g$$ per litre?
A
25.5 $$g$$
B
3.0 $$g$$
C
3.2 $$g$$
D
4.2 $$g$$
Answer :
3.2 $$g$$
Strength of the solution $$ = 34\,g/L$$
$$1\,L$$ of the solution contains $$34\,g$$ of $${H_2}{O_2}$$
$$200\,mL$$ of the solution contains $$\frac{{34}}{{1000}} \times 200 = 6.8\,g$$ of $${H_2}{O_2}$$
$$\mathop {2{H_2}{O_2}}\limits_{2 \times 34\,g} \to 2{H_2}O + \mathop {{O_2}}\limits_{32\,g} $$
$$68\,g$$ of $${H_2}{O_2}$$ gives $$32\,g$$ of $${O_2}$$
$$6.8\,g$$ of $${H_2}{O_2}$$ gives $$ = \frac{{32}}{{68}} \times 6.8 = 3.2\,g$$ of $${O_2}$$
70.
Which of the following reactions increases production of dihydrogen from synthesis gas?
A
\[C{{H}_{4\left( g \right)}}+{{H}_{2}}{{O}_{\left( g \right)}}\xrightarrow[Ni]{1270\,K}C{{O}_{\left( g \right)}}+3{{H}_{2\left( g \right)}}\]
B
\[{{C}_{\left( s \right)}}+{{H}_{2}}{{O}_{\left( g \right)}}\xrightarrow{1270\,K}C{{O}_{\left( g \right)}}+{{H}_{2\left( g \right)}}\]
C
\[C{{O}_{\left( g \right)}}+{{H}_{2}}{{O}_{\left( g \right)}}\xrightarrow[\text{Catalyst}]{673\,K}\] \[C{{O}_{2\left( g \right)}}+{{H}_{2\left( g \right)}}\]
D
\[{{C}_{2}}{{H}_{6\left( g \right)}}+2{{H}_{2\left( g \right)}}O\xrightarrow[Ni]{1270\,K}\] \[2C{{O}_{\left( g \right)}}+5{{H}_{2\left( g \right)}}\]
Answer :
\[C{{O}_{\left( g \right)}}+{{H}_{2}}{{O}_{\left( g \right)}}\xrightarrow[\text{Catalyst}]{673\,K}\] \[C{{O}_{2\left( g \right)}}+{{H}_{2\left( g \right)}}\]
The production of dihydrogen can be increased by reacting carbon monoxide of syngas mixtures with steam in the presence of iron chromate as catalyst.
\[C{{O}_{\left( g \right)}}+{{H}_{2}}{{O}_{\left( g \right)}}\xrightarrow[\text{Catalyst}]{673\,K}\] \[C{{O}_{2\left( g \right)}}+{{H}_{2\left( g \right)}}\]
This is called water - gas shift reaction.