Which of the following is NOT a type of chemical reaction?
Combination reaction
Decomposition reaction
Condensation reaction
Displacement reaction
(3) Condensation reaction
What is observed when quicklime (CaO) is added to water?
No reaction occurs
Bubbles are formed
A highly exothermic reaction takes place
A gas is evolved
(3) A highly exothermic reaction takes place
Which gas is released when hydrochloric acid reacts with zinc?
Oxygen
Hydrogen
Carbon dioxide
Nitrogen
(2) Hydrogen
What is the color change observed when iron nails are placed in copper sulfate solution?
No color change
The solution turns blue
The solution turns green
The solution turns colorless
(3) The solution turns green
Which of the following statements is true about a redox reaction?
Both oxidation and reduction occur simultaneously
Only oxidation occurs
Only reduction occurs
Neither oxidation nor reduction occurs
(1) Both oxidation and reduction occur simultaneously
Which of the following reactions is an endothermic reaction?
Burning of coal.
Decomposition of vegetable matter into compost.
Process of respiration.
Decomposition of calcium carbonate to form quick lime and carbon dioxide.
(2)
Decomposition of calcium carbonate to form quick lime and carbon dioxide is an endothermic reaction since this process absorbs heat from atmosphere.
Zn + HCl ? Zn + _______
Zn
None of these
(1)
Zn + HCl ? Zn
Displacement reaction is a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions.
Which among the following statement(s) is (are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to:
(i) The formation of silver by decomposition of silver chloride.
(ii) Sublimation of silver chloride.
(iii) Decomposition of chlorine gas from silver chloride.
(iv) Oxidation of silver chloride.
(i) only
(i) and (iii)
(ii) and (iii)
(iv) only
(1)
Exposure of silver chloride to sunlight for a long duration turns silver chloride grey due to the photolysis reaction in which the decomposition of silver chloride takes place in the presence of sunlight, leading to the formation of silver.
The reaction which decomposes after the supply of heat is called ______.
Thermal decomposition
Combination reaction
Redox reaction
Displacement reaction
(1)
A thermal decomposition reaction occurs when heat is applied to a compound causing it to decompose (break down) into multiple different chemical substances. An example is when baking soda (sodium bicarbonate) is heated:
In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution:
(i) exchange of atoms takes place.
(ii) exchange of ions takes place.
(iii) a precipitate is produced.
(iv) an insoluble salt is produced.
The correct option is:
(ii) and (iv)
(i) and (iii)
only (ii)
(ii), (iii) and (iv)
(4)
In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution, sodium sulphate chemically reacts with barium chloride in the form of their aqueous solution to form an insoluble white precipitate of barium sulphate and sodium chloride.
(insoluble)
Here, exchange of ions takes place.
