Tag: chemistry

Questions Related to chemistry

HCl can be prepared by:

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  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).

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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?

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

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

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Correct Option: C
Formation of $HCl$ from its elements takes place in the presence of sunlight.
chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  1. True

  2. False

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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.

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

The compound which does not have oxygen is :

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  1. nitric acid

  2. sodium hydroxide

  3. hydrochloric acid

  4. acetic acid

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Correct Option: C
Explanation:

Nitric acid $(HNO _3)$ has 3 oxygen atoms in its formula.

Sodium hydroxide $(NaOH)$ has 1 oxygen atom in its formula.
Acetic acid $(CH _3COOH)$ has 2 oxygen atoms in its formula.
Hydrochloric acid $(HCl)$ does not have oxygen atom in its formula.

Hence, option C is correct.

Identify the gas evolved when potassium sulphite is treated with dilute hydrochloric acid.

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  1. ${ S } _{ 2 }$

  2. ${ O } _{ 2 }$

  3. ${ SO } _{ 2 }$

  4. None of these

Show answer
Correct Option: C
Explanation:

When potassium sulphite is treated with dilute hydrochloric acid, sulphur dioxide gas is evolved along with potassium chloride and water.


$ { K } _{ 2 }{ SO } _{ 3 }+HCl\rightarrow KCl + { H } _{ 2 }O+{ SO } _{ 2 }$

Hence, option C is correct.

Which of the following gas is evolved when concentrated hydrochloric acid is made to react with manganese dioxide?

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  1. ${ O} _{ 3 }$

  2. ${ O } _{ 2 }$

  3. ${ H} _{ 2 }$

  4. ${ Cl } _{ 2 }$

Show answer
Correct Option: D
Explanation:

When concentrated hydrochloric acid reacts with manganese dioxide, chlorine gas as well as manganese(II) chloride and water. 


${ MnO } _{ 2 }+4HCl\rightarrow { MnCl } _{ 2 }+{ Cl } _{ 2 }+2{ H } _{ 2 }O$

Hence, option $\text{D}$ is correct.

Iron reacts with hydrogen chloride gas-forming (iron [II] chloride, iron [III] chloride) and hydrogen, The reaction is an example of :

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  1. double decomposition

  2. synthesis

  3. simple displacement

  4. None of these

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Correct Option: C
Explanation:

Iron reacts with hydrogen chloride gas-forming iron$ [II] $ chloride and hydrogen. The reaction is an example of simple displacement reaction.


$Fe + 2HCl \longrightarrow FeCl _2 + H _2$


Hence, the correct answer is option $\text{D}$.

Hydrochloric acid can be converted into chlorine by heating with :

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  1. calcium oxide

  2. lead [III] oxide

  3. lead [IV] oxide

  4. lead [II] oxide

Show answer
Correct Option: C
Explanation:

Explanation :-

In $HCl$, the chlorine atom present with $-1$ oxidation state and $Cl _2$ has zero oxidation state. It means chlorine undergoes reduction that is only possible in the presence of a strong oxidizing agent.

$\underset{agent (Pb \ in \ +4 \ state)}{\underset{strong \ oxidizing}{PbO _2}} + 4HCl \rightarrow PbCl _2 + Cl _2 + 2H _2O$

Compounds $A$ and $B$ are treated with dilute $HCl$ separately. The gases liberated are $Y$ and $Z$ respectively $Y$ turns acidified dichromate paper green while $Z$ turns lead acetate paper black. So $A$ and $B$ compounds are respectively:

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  1. $Na _2SO _3, Na _2S$

  2. $NaCl, Na _2CO _3$

  3. $Na _2S, Na _2SO _3$

  4. $Na _2SO _3, K _2SO _4$

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Correct Option: A

On adding few drops of dil. HCl to freshly precipitated ferric hydroxide, a red coloured colloidal solution is obtained. The phenomenon is known as :

chemistry study of compounds a. hydrogen chloride laboratory method of preparation of hydrochloric acid physical and chemical properties and uses of hydrochloric acid hydrogen chloride: occurrence, preparation, purification and identification

  1. protective action

  2. flocculation

  3. coagulation

  4. peptisation

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Correct Option: D
Explanation:

Peptization is the process of forming stable colloids by using an electrolyte to break up a precipitate and disperse it into the colloid


Hence, option D is correct.