Chemistry

Chemical Reactions and Processes

571 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 distinguish between black copper oxide and black manganese dioxide practical work chemistry

Why should the reaction between manganese dioxide and hydrochloric acid carried out in a fume cupboard?

  1. Manganese causes skin irritations

  2. Both reactants and products causes itching

  3. Chlorine gas is poisonous

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

When manganese dioxide is treated with hydrochloric acid, chlorine gas is released as a product which can be poisonous. Hence, the procedure should take place in a fume cupboard to prevent any harmful effects.

Multiple choice distinguish between black copper oxide and black manganese dioxide practical work chemistry

The reaction between copper oxide and hydrochloric acid is a:

  1. acid base reaction

  2. replacement reaction

  3. combustion reaction
  4. both $A$ and $B$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The reaction copper oxide and hydrochloric acid is an acid-base reaction due to the hydrogen and oxygen found in the reactants, then forming water ($H _2O$). This is also a replacement reaction because the copper ($Cu$) is "swapping out" with the hydrogen ($H$) creating two different molecules.

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.
$Acid + Metal\ carbonate \rightarrow Salt + Water + Carbon\ dioxide$