Tag: hydrogen chloride: occurrence, preparation, purification and identification

Questions Related to hydrogen chloride: occurrence, preparation, purification and identification

Select the correct statement among the following.

  1. Hydrogen chloride is prepared by passing chlorine gas through hot water

  2. Hydrogen chloride is produced by combination of moist hydrogen gas with chlorine in the presence of diffused sunlight

  3. Hydrogen chloride can't be produced in the dark

  4. Activated carbon is used as a catalyst in the synthesis of hydrogen chloride


Correct Option: B,D
Explanation:
Hydrogen chloride is produced by a combination of moist hydrogen gas with chlorine in the presence of diffused sunlight. The reaction should be maintained in diffused but not in direct sunlight as it is an explosive reaction. And not even in dark as it is very slow (negligible). Activated carbon is used as a catalyst in the synthesis of hydrogen chloride.
Hence, options $B$ and $D$ are correct.

Moist hydrogen gas combines with chlorine in the presence of diffused sunlight to form $HCl$. The catalyst used here is :

  1. oxygen.

  2. silica.

  3. alum.

  4. moisture.


Correct Option: D
Explanation:

Moisture acts as a catalyst in the formation of HCl gas.


It acclerates the reaction.

It provides a reacting medium to hydrogen and chlorine gas.

It increases the interaction between them.


Hence, the correct option is $D$.


The reaction equation of the preparation of $HCl$ by synthesis is given by:

  1. $NaCl + H _2SO _4 \rightarrow NaHSO _4+HCl$

  2. $NaHSO _4+NaCl \rightarrow HCl+NaSO _4$

  3. $H _2+Cl _2 \rightarrow 2HCl$

  4. None of these


Correct Option: C
Explanation:
In the chloralkali process, brine (mixture of sodium chloride and water) solution is electrolyzed producing chlorine (Cl$ _2$), sodium hydroxide, and hydrogen (H$ _2$):

2 NaCl + 2 H$ _2$O → Cl$ _2$ + 2 NaOH + H$ _2$

The pure chlorine gas can be combined with hydrogen to produce hydrogen chloride in the presence of UV light:

Cl$ _2$(g) + H$ _2$(g) → 2 HCl(g)

As the reaction is exothermic, the installation is called an HCl oven or HCl burner. The resulting hydrogen chloride gas is absorbed in deionized water, resulting in chemically pure hydrochloric acid. This reaction can give a very pure product, e.g. for use in the food industry.

Hence, the correct option is $\text{C}$

In the laboratory preparation of $HCl$, which of the following are preferred?

  1. Conc. $H _2SO _4$ as reactant

  2. Conc. $H _2SO _4$ as drying agent

  3. Temperature of reaction mixture below $200^0C$

  4. Use of activated carbon as catalyst


Correct Option: A,B,C
Explanation:

The laboratory preparation of $HCl$ includes dehydration of hydrochloric acid with sulphuric acid. It can also be generated by the reaction of sulphuric acid with sodium chloride. 


The reaction occurs at room temperature. Sulphuric acid acts as a reactant as well as a drying agent.

$NaCl+H _2SO _4 \rightarrow NaHSO _4+HCl$

Hence, the correct options are $\text{A}$, $\text{B}$ and $\text{C}$

Metal chloride + Sulphuric acid$\longrightarrow$.............. + Hydrogen chloride :

  1. Metallic sulphate

  2. Metallic bisulphate

  3. Metallic sulphide

  4. None of the above


Correct Option: C
Explanation:

Metal chloride reaction with sulphuric acid is a double displacement reaction which form a metallic sulphate.

For example :-
$Na _2SO _4$ formed when $NaCl$ reacts with $H _2SO _4$ as

$\underset{chloride}{\underset{metal}{2NaCl}} + \underset{acid}{\underset{sulphuric}{H _2SO _4}} \xrightarrow{\Delta} \underset{Sulphate}{\underset{metallic}{Na _2SO _4}} + \underset{chloride}{\underset{Hydrogen}{2HCl}}$

The reaction of moist hydrogen gas with chlorine is explosive in the presence of :

  1. hydrogen

  2. oxygen

  3. darkness

  4. direct sunlight


Correct Option: D
Explanation:

The reaction of chlorine with moist hydrogen gas is explosive in case of direct sunlight.

In dark no reaction will take place because for activation light is required.
Hence, $HCl$ is prepared in presence of diffused sunlight.

Drying agents used in the purification of hydrogen chloride is/are:

  1. conc. $H _2SO _4$

  2. $P _2O _5$

  3. $CaO$

  4. all of the above


Correct Option: A
Explanation:

Conc. $H _2SO _4$ is a very strong drying agent and it is used in purification of hydrogen chloride.

HCl can be prepared by:

  1. $NaCl$ + $H _{2}SO _{4}$$\overset{420K}\rightarrow$

  2. $NaHSO _{4}$ + $NaCl$ $\overset{823K}\rightarrow$

  3. $NaNO _3$ + $H _{2}SO _{4}$ $\rightarrow$

  4. both (A) and (B).


Correct Option: D
Explanation:
HCl can be prepared by following :

$NaCl$ + $H _{2}SO _{4}$$\overset{420K}\rightarrow NaHSO _4+HCl$

$NaHSO _{4}$ + $NaCl$ $\overset{823K}\rightarrow Na _2SO _4+HCl$.

Hence option D is correct.

In which reaction equilibrium moves in left hand side when pressure is increased?

  1. $H _{2(g)} + Cl _{2(g)} \rightleftharpoons 2HCl _{(g)}$

  2. $2Mg _{(s)} + O _{2(g)} \rightleftharpoons 2MgO _{(s)}$

  3. $2H _{2}O _{(g)} \rightleftharpoons 2H _{2(g)} + O _{2(g)}$

  4. $N _{2(g)} + 3H _{2(g)} \rightleftharpoons 2NH _{3(g)}$


Correct Option: C
Formation of $HCl$ from its elements takes place in the presence of sunlight.
  1. True

  2. False


Correct Option: A
Explanation:

Hydrogen chloride is prepared from chlorine gas and hydrogen gas in the presence of UV light. This reaction is exothermic and the resulting HCl gas is absorbed in deionized water.

${ H } _{ 2 }+{ Cl } _{ 2 }\rightarrow 2HCl$