Tag: chemistry

Questions Related to chemistry

$HCl$ gas cannot be dried by passing through:

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. $H _{2}SO _{4}$

  2. $CaO$

  3. $P _{2}O _{5}$

  4. $CO$

Show answer
Correct Option: B,C
Explanation:

$CaO$ and $P _2O _5$ are basic in nature so when $HCl$ is based over them, they will react with $HCl$ and form Salt and water, whereas $H _2SO _4$ and $CO$ are an acidic and hence greater affinity for water. So they can be used to dry $HCl$.

$HCl$  gas does not effect a dry strip of blue litmus paper but it turns red in the presence of a drop of water ?

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. Blue litmus paper in the presence of water accepts the proton from $HCl$ and turns blue to red

  2. Blue litmus paper in the presence of water accepts the chloride ion from $HCl$ and turns blue to red

  3. Blue litmus paper in the presence of water with acid do not turn into red

  4. None of the above 

Show answer
Correct Option: A
Explanation:

A dry litmus paper will not show any effect in the presence of dry HCL due to the absence of moisture ($H^+$ ions) in the litmus paper, whereas on putting a drop of water, the blue litmus paper immediately turns to red due to the presence of water in it hence presence of hydrogen ions ($H^+$ ions).


Hence, option A is correct.

When phosphorous pentoxide is reacted with $HCl$ gas, products are:

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. $POCl _3$

  2. $P _4O _{10}$

  3. $H _3PO _2$

  4. $HPO _3$

Show answer
Correct Option: A,D
Explanation:

Phosphorous pentoxide reacts with $HCl$ to form Phosphorous Oxychloride and metaphosphoric acid.


$2P _2O _5 + 3HCl \rightarrow POCl _3 + 3HPO _3$


Hence, $POCl _3$ and $HPO _3$ are correct.

Observing the method of collection of the gas, what you can tell about the density of hydrogen chloride?

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. A gas that is more dense than air

  2. A gas that is less dense than air

  3. A gas (liqued form ) that is less dense than air

  4. None of these

Show answer
Correct Option: A
Explanation:

A gas that is more dense than air can be collected by downward delivery. Examples of gases that can be collected by this method are carbon dioxide, chlorine, HCl, sulphur dioxide.

Which compound(s) is/are produced when hydrochloric acid is added to silver nitrate solution?

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. ${ HNO } _{ 3 }$

  2. $AgCl$

  3. Both A and B

  4. None of these

Show answer
Correct Option: C
Explanation:

${ AgNO } _{ 3 }+HCl\rightarrow AgCl+{ HNO } _{ 3 }$

$HCl$ is prepared by heating $NaCl$ with $conc.{ H } _{ 2 }S{ O } _{ 4 }$. But $HI$ cannot be prepared by treating $NaI$ with $conc.{ H } _{ 2 }S{ O } _{ 4 }$. Identify the reason.

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. ${ H } _{ 2 }S{ O } _{ 4 }$ is oxidised by $HI$ and not oxidised by $HCl$

  2. $HI$ is oxidised by ${ H } _{ 2 }S{ O } _{ 4 }$ and $HCl$ is not oxidised by $HI$

  3. $HI$ dissociates on treatment with ${ H } _{ 2 }S{ O } _{ 4 }$ and $HCl$ does not dissociate

  4. Reaction of ${ H } _{ 2 }S{ O } _{ 4 }$ with $HI$ is reversible whereas with $HCl$ is irreversible

Show answer
Correct Option: B
Explanation:

$HCl$ is prepared by heating $NaCl$ with $conc.{ H } _{ 2 }S{ O } _{ 4 }$. But $HI$ cannot be prepared by treating $NaI$ with $conc.{ H } _{ 2 }S{ O } _{ 4 }$. Because  $HI$ is oxidised by ${ H } _{ 2 }S{ O } _{ 4 }$ and $HCl$ is not oxidised by $HI$.

Hence, option $B$ is correct.

Glaber prepared $HCl$ from which of the following compounds?

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. $NaCl,H _2SO _4$

  2. $NaCl,H _2CO _3$

  3. $NaCl,HNO _3$

  4. $KCl,H _2SO _4$

Show answer
Correct Option: A
Explanation:

Glaber is the scientist who prepared hydrogen chloride in the laboratory by reacting sodium chloride with concentrated sulphuric acid.

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

Sodium bisulphate is a by-product in the above reaction . This is insoluble. Therefore, we further add it with more sodium chloride. This mixture has to be heated to a higher temperature of around 823K. It gives dissolvable sodium sulfate and HCl gas.

$NaHSO _4+NaCl\rightarrow Na _2SO _4+HCl$.

Hence option $A$ is correct.

In the Hydrolysis of ICl , the products are :

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. HI +HCl

  2. HI +HOCl

  3. HCl+HOI

  4. HOCl +HOI

Show answer
Correct Option: C
Explanation:

In the hydrolysis of ICl, the products are HCl + HOI.


$ICl+H _2O\rightarrow HCl+HOI$

During the hydrolysis of interhalogen compounds, oxyacid of less electronegative or large sized halogen is formed, and other halogen forms halogen acid. 

Thus, less electronegative iodine forms HOI and more electronegative chlorine forms HCl.

The pain due to honey-bee siting can be relieved by using:

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. washing soda

  2. water

  3. acid

  4. baking soda

Show answer
Correct Option: D
Explanation:

Honey bee sting has formic acid in it which causes irritation and burns.

To neutralise this effect, we recommend a base to be used.
Hence, bee sting can be relieved using baking soda. 

Which of the following acid is used in fire extinguishers?

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. Hydrochloric acid

  2. Sulphuric acid

  3. Nitric acid

  4. Oxalic acid

Show answer
Correct Option: B
Explanation:

Soda-acid extinguisher uses the reaction between sodium bicarbonate solution and sulphuric acid to expel pressurized water onto a fire. The reaction takes place as follows :-

$2NaHCO _3+H _2SO _4 \rightarrow Na _2SO _4+2CO _2+2H _2O$
The $CO _2$ formed forces the water out of the discharge and hence the device must be held in upright position.
However, such extinguisher can't be used in case of fire caused due to electricity (as water is a good conductor of electricity) and fire caused due to oil or petrol (as the oil or petrol may float over water).
Thus, the correct answer is option (B).