1. Strong heating of ferrous sulphate leads to the formation of a brown solid and two This reaction can be categorised as _______.
A. Displacemnt and redox
B. Decomposition and redox
C. Displacement and endothermic
D. Decomposition and exothermic
ANSWER:B.Decomposition and redox
SOLUTION : Therefore, Strong heating of ferrous sulphate leads to the formation of a brown solid and two gases. This reaction can be categorised as option (B) decomposition and redox./p>
2. Before burning in air, the magnesium ribbon is cleaned by rubbing with a sand to ________.
A. Make the ribbon surface shinier
B. Remove the layer of magnesium oxide from the ribbon surface
C. Remove the layer of magnesium carbonate from the ribbon surface
D. Remove the moisture from the ribbon surface
ANSWER:A.Make the ribbon surface shinier
SOLUTION:Magnesium ribbon is cleaned with a sand paper before burning to remove the layer of magnesium oxide. Magnesium, we know is a very reactive metal.
3. A substance added to food containing fats and oils is called ____.
A. Oxidant
B. Rancid
C. Coolant
D. Antioxidant
ANSWER :D.Antioxidant
SOLUTION:Antioxidants are added to foods containing fats/oil.
4. In a chemical reaction between sulphuric acid and barium chloride
solution the white precipitates formed are of ______.
A. Barium sulphate
B. Chlorine
C. Sulphur
D. None of these
ANSWER: A.Barium sulphate
SOLUTION: On reaction with the sulphuric acid solution, barium chloride forms a white precipitate of barium sulfate.
5. The respiration process during which glucose undergoes slow combustion by combining with oxygen in the cells of our body to produce energy, is a kind of _________
A. Exothermic process
B. Endothermic process
C. Reversible Process
D. Physical Process
ANSWER: A.Exothermic process
SOLUTION:
In respiration, glucose undergoes slow combustion by combining with oxygen to form carbon dioxide, water and energy. Apart from other functions, this energy maintains our body heat. Due to this production of energy, respiration is considered an exothermic process.
6. Which of the following gases is used in the storage of fat and oil containing foods for a long time?
A. Carbon dioxide gas
B. Oxygen gas
C. Nitrogen gas
D. Neon gas
ANSWER: C.Nitrogen gas
SOLUTION: Thus, among the given options, Nitrogen gas (option second) is used in the storage of fat and oil-containing foods for a long time.
7. Which of the following is not a physical change?
A. Boiling of water to give water vapours
B. Melting of ice to give water
C. Dissolution of salt in water
D. Combustion of Liquefield Petroleum gas
ANSWER: D.Combustion of Liquefield Petroleum gas
SOLUTION :
Hence, the correct option is D i.e. Combustion of Liquefied Petroleum Gas (LPG).
8. Which one of the following processes involve chemical reactions?
A. Storing of oxygen gas under pressure in a gas cylinder
B. Liquefaction of air
C. Keeping petrol in a china dish in the open
D. Heating copper wire in presence of air at high temperature
ANSWER: D.Heating copper wire in presence of air at high temperature
SOLUTION:Hence, Heating copper wire in the presence of air at high temperature is a process that involves chemical reaction.
9. The Compound obtained on reactions of iron with steam is /are _________.
A. FeO
B. Fe3O4
C. FeO
D. Fe2O3
ANSWER: B.Fe3O4
SOLUTION:Iron reacts with steam to form iron oxide and hydrogen gas. The reaction occurs as follows: 3Fe (s)+4H2O (g)→Fe3O4(s)+4H2(g)
10. In which of the following the identity of initial substance remains unchanged?
A. Curdling of milk
B. Formation of crystals by process of crystallisation
C. Fermentation of grapes
D. Digestion of food
ANSWER: B.Formation of crystals by process of crystallisation
SOLUTION:
Hence, among the following options, the identity of the initial substance remains unchanged in option(B) the Formation of crystals by process of crystallization.