Chemistry

Chemical Reactions and Processes

626 Questions

Chemical reactions and processes questions cover the transformation of substances through electrolysis, thermal decomposition, and catalysis. Key areas include identifying gas evolution, balancing chemical equations, and understanding industrial chemical applications. This general chemistry topic is a staple in the science sections of multiple competitive examinations.

Thermal decompositionElectrolysis processGas evolution reactionsHeterogeneous catalystsFuel cell components

Chemical Reactions and Processes Questions

Multiple choice reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

Soda-acid fire extinguisher extinguishes the fire by :

  1. cutting the supply of air

  2. removing the combustible substance

  3. raising the ignition temperature

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The principle of working of fire extinguisher is based on either of the following three conditions: 
• cooling the combustible material below its ignition temperature, or 
• cutting off the supply of air, or 
• cooling the combustible material and at the same time cutting the supply of air. 

Multiple choice chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

How is $ {P}{Cl} _{3} $ produced industrially?

  1. Reacting chlorine with white phosphorus

  2. Reacting chlorine with phosphorus acid

  3. Reacting chlorine with black phophorous

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Industrially Phosphorous trichloride is prepared by the reaction of Chlorine with a solution of white Phosphorous in phosphorous trichloride.
The reaction is given by:
$P _4$ $+$ $6Cl _2$ $\longrightarrow $ $4PCl _3$
Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

Acids react with carbonate and bicarbonates to liberate $CO _{2}$.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The metal ion displaces the proton $(H^+)$ from the acid and a salt is formed along with carbonic acid $(H _2CO _3)$

However, $(H _2CO _3)$ is unstable in atmospheric conditions.
$MgCO _3+2HCl\longrightarrow MgCl _2+H _2CO _3$ (Equation $01$)
$H _2CO _3\longrightarrow H _2O+CO _2$ (Equation $02$)
By adding $01$ and $02$
$MgCl _2+2HCl\longrightarrow MgCl _2+H _2O+CO _2$
Similarly,
$Na _2CO _3+H _2SO _4\longrightarrow Na _2SO _4+H _2CO _3$
here, $H _2CO _3$ is split into $H _2O+CO _2$
$ZnCO _3+2HNO _3\longrightarrow Zn(NO _3) _2+H _2O+CO _2$

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

_________ causes bubble formation when acid reacts with carbonates.

  1. Salt
  2. $CO _{2}$

  3. Water

  4. Oxygen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When acids react with carbonates, such as calcium carbonate (found in chalk, limestone and marble) a salt, water and carbon dioxide are made. Carbon dioxide is formed as by product which causes bubbling during the reaction and can be detected using limewater.
$Acid + Metal\ carbonate \rightarrow Salt + Water + Carbon\ dioxide$

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

Why does baking soda and vinegar react with each other?

  1. Undergo acid base reaction

  2. Exchange atoms
  3. Both $(A)$ and $(B)$

  4. High temperature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Baking soda and vinegar react with each other because of an acid-base reaction. Baking soda is a bicarbonate $(NaHCO _{3})$ and vinegar is an acetic acid $(HCH _{3}COO)$. One of the products this reaction creates is carbon dioxide. Also Baking soda and vinegar react with each other because they exchange atoms. In this case, they are exchange a proton, which is a subatomic particle that makes atoms.

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

When sulphuric acid reacts with calcium carbonate, ________ is formed.

  1. calcium sulphate

  2. calcium

  3. calcium hydroxide

  4. hydrogen gas
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sulphuric acid gives calcium sulphate, carbon dioxide gas and water when it reacts with calcium carbonate.
$CaC{O} _{3}   +   {H} _{2}S{O} _{4}   \rightarrow   CaS{O} _{4}   +   C{O} _{2}   +   {H} _{2}O$.

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

Why do the gas released when metal bicarbonates react with acid turns lime water milky?

  1. Formation of calcium hydrogen carbonate

  2. Precipitation of calcium hydrogen carbonate

  3. Formation of white calcium carbonate precipitate

  4. None of above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When metal bicarbonates react with acid liberates carbon dioxide The gas evolved because of reaction of acid with metal carbonate or metal hydrogen carbonate turns lime water milky. This shows that the gas is carbon dioxide gas. This happens because of formation of white precipitate of calcium carbonate.
$Ca{\left(OH\right)} _{2}  + C{O} _{2}    \Rightarrow   CaC{O} _{3}  +  {H} _{2}O$.

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

What is used with acid in fire extinguisher to produce carbon dioxide gas?

  1. Metal oxide

  2. Metal hydrogen carbonate

  3. Metallic acid

  4. Base
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Metal carbonate or metal hydrogen carbonate and acid are used in fire extinguisher to produce carbon dioxide gas. Acid and metal carbonate or bicarbonate are kept in separate chambers in a fire extinguisher. On emergency, they are allowed to react with one another. The carbon dioxide gas so produced is poured over fire. As carbon dioxide does not support burning, it puts off the fire.

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

The gas released when $NaHCO _3$ reacts with $HNO _3$ will:

  1. turn lime water milky

  2. release effervescence
  3. both $A$ and $B$

  4. burns with a pop sound
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

On adding a hydrogen carbonate to an acid, effervescence from carbon dioxide gas is released along with the formation of water and salt. $CO _2$ turns lime water milky.
$ NaHCO _3 + HNO _3 \rightarrow NaNO _3 + H _2O + CO _2 $

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains:

  1. $NaCl$
  2. $HCl$
  3. $LiCl$
  4. $KCl$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Crushed egg shell has composition $CaCO _3$ reacts with acid and gives gas $CO _2$ which turns lime water $(Ca(OH) _2)$ milky by producing $CaCO _3$ again. The acid in given options is $HCl$. 

$CaCO _3 + 2HCl \rightarrow CaCl _2 + CO _2 + H _2O $
$Ca(OH) _2 + CO _2 \rightarrow CaCO _3 + H _2O$

Multiple choice chemistry acids and alkalis acids with carbonates reactions of acids and bases properties of acids and bases

Which of the following represents the products obtained when, $HCl$ reacts with sodium hydrogen carbonate?

  1. $NaCl$, $H _2O$ and $CO _2$
  2. $NaCl$ and $CO _2$
  3. $NaOH$ and $CO _2$
  4. $NaOH$, $H _2O $ and $CO _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When $HCl$ reacts with sodium hydrogen carbonate, the products obtained are $NaCl,$ $H _2O$ and $CO _2$.
$\displaystyle NaHCO _3 + HCl \rightarrow NaCl + H _2O + CO _2$