1. Which of the following does not involve a chemical reaction ?

Melting of candle wax on heating

Burning of candle wax when heated

Digestion of food in our body

Process of respiration

Answer: Melting of candle wax on heating


2. Dissolving sugar is an example of ?

Redox Reaction

Chemical change

Physical change

None of these

Answer: Physical change


3. Which of the following is a thermal decomposition reaction ?

ZnCO3 -> ZnO + CO2

H2(g) + Cl2(g) -> 2HCl(g)

2AgCl -> 2Ag + Cl2

2H2O -> 2H2 + O2

Answer: ZnCO3 -> ZnO + CO2


4. What is observed when a solution of potassium iodide is added to silver nitrate solution ?

White precipitate of silver iodide is formed

Agl is soluble in water

No reaction takes place

yellow precipitate of Agl is formed

Answer: yellow precipitate of Agl is formed


5. A substance added to food containing fats and oils is called ?





Answer: Antioxidant


6. The process of reduction involves ?

addition of hydrogen

removal of hydrogen

addition of oxygen

removal of oxygen

Answer: addition of hydrogen


7. The following reaction is an example of a 4NH3(g) + 5O2(g) -> 4NO(g) + 6H2O(g) (i) displacement reaction (ii) combination reaction (iii) redox reaction (iv) neutralisation reaction ?

(iii) and (iv)

(ii) and (iii)

(i) and (iv)

(i) and (iii)

Answer: (i) and (iii)


8. Which of the following is (are) an endothermic process(es) (z) Dilution of sulphuric acid (ii) Sublimation of dry ice (iii) Condensation of water vapours (iv) Evaporation of water ?

(iii) only

(ii) and (iv)

(ii) only

(i) and (iii)

Answer: (ii) and (iv)


9. Bhanu Appeared In Class Test Where He Wrote Some Statements But He Confused To Know The Correct Statement. Would You Help Him To Know That ?

The orange colour of potassium dichromate solution changes to green when sulphur dioxide gas is passed through acidified potassium dichromate solution.

Some chemical reaction and are characterized by a change in colour.

The purple colour of potassium permanganate solution disappears when citric acid reacts with potassium permanganate solution.

All the above.

Answer: All the above.


Here are all the statements are correct. Hence, your answer will be option [D]

10. The Following Reaction Is An Example Of A: 4NH3 (G) +5O2 (G) -> 4NO (G) + 6H2O (G) ?

Redox reaction, neutralisation reaction

Displacement reaction, redox reaction

Displacement reaction, neutralisation reaction

Combination reaction, redox reaction

Answer: Displacement reaction, redox reaction


This is a redox reaction because oxidation and reduction both are happening simultaneously. It is also a displacement reaction because H of NH3 is displaced by oxygen. A displacement reaction is also a redox reaction as it is always followed by oxidation as well as reduction. Note: When oxygen is added to a compound in a reaction, it is called oxidation. Removal of oxygen from a substance during a reaction is called reduction.