Question

21. The substance that will be flattened on beating with a hammer is *

crystal of iodine

lump of sulphur

piece of coal

zinc granule

22. The solution of ash of magnesium ribbon is *

acidic

basic

neutral

all of these

23. Which of the following metals do not react even with steam? *

Silver

Iron

Calcium

Sodium

24. Which of the following order is correct for the reactivity of metals? *

Na> Au > Fe > Mg

Na> Mg > Fe > Au

Mg> Fe > Na > Au

Mg> Na > Fe > Au

25.Fire proof plastic uniform worn by fire fighters has a coating of _____ to make it fire resistant *

Nylon

Rayon

Melamine plastic

Silk

26. Fibres of _______ resemble that of silk and hence, it is popularly known as ‘artificial silk’ *

acrylic

polyester

rayon

nylon

27. The fibres made up by the chemical treatment of wood pulp is *

Rayon

Nylon

Polyester

None of these

28. Which amongst the following is used in the manufacturing of perfumes? *

Coal tar

Coal gas

Coke

Kerosene

29. Identify the gas that is generally produced when coal is burnt in the presence of a lot of air. *

Carbon monoxide

Sulphur dioxide

Nitrogen dioxide

Carbon dioxide

30. Use of CNG in automobile is better than petrol because it is *

cheaper

less polluting

cannot be adulterated

All of the above​

Answer 1

21. Zinc granule

22. Basic

23. Silver

24. Na> Mg > Fe > Au

25. Melamine plastic

26. Rayon

27. Rayon

28. Coal tar

29. Carbon dioxide

30. All of these