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

Explanation:


2. Dissolving sugar is an example of ?

Redox Reaction

Chemical change

Physical change

None of these

Answer: Physical change

Explanation:


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

Explanation:


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

Explanation:


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

Coolant

Antioxidant

Rancid

Oxidant

Answer: Antioxidant

Explanation:


6. The process of reduction involves ?

addition of hydrogen

removal of hydrogen

addition of oxygen

removal of oxygen

Answer: addition of hydrogen

Explanation:


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)

Explanation:


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)

Explanation:


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.

Explanation:

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

Explanation:

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.