1. Which of the following statements are true for pure substances?(i) Pure substances contains only one kind of particles.(ii) Pure substances may be compounds or mixtures.(iii) Pure substances have the same composition throughout.(iv) Pure substances can be exemplified by all elements(b) dissolution and it is a physical change.(c) corrosion and it is a chemical change.(d) dissolution and it is a chemical change.Ans : (c) corrosion and it is a chemical change.3. A mixture of sulphur and carbon disulphide is :(a) heterogeneous and shows Tyndall effect.(b) homogeneous and shows Tyndall effect.(c) heterogeneous and does not show Tyndall effect.(d) homogeneous and does not show Tyndall effect. Ans : (d) homogeneous and does not show Tyndall effect.4. Tincture of iodine has antiseptic properties. This solution is made by dissolving :(a) Iodine in potassium iodide(b) Iodine in vaseline(c) Iodine in water(d) Iodine in alcoholAns : (d) Iodine in alcohol.5. Which of the following are homogeneous in nature?(i) Ice(ii) Wood(iii) Soil(iv) Air(a) (i) and (iii) (b) (ii) and (iv)(c) (i) and (iv) (d) (iii) and (iv)Ans : (c) (i) and (iv)6. Which of the following are physical changes?(i) Melting of iron metal(ii) Rusting of iron(iii) Bending of an iron rod(iv) Drawing a wire of iron metal(a) (i), (ii) and (iii) (b) (i), (ii) and (iv)(c) (i), (iii) and (iv) (d) (ii), (iii) and (iv)Ans : (c) (i), (iii) and (iv)7. Which of the following are chemical changes?(i) Decaying of wood(ii) Burning of wood(iii) Sawing of wood(iv) Hammering of a nail into a piece of wood(a) (i) and (ii) (b) (ii) and (iii)(c) (iii) and (iv) (d) (i) and (iv)Ans : (a) (i) and (ii)8. Two substances, A and B were made to react to form a third substance, A B according to the followingother than nickel.(a) (i) and (ii) (b) (i) and (iii)(c) (iii) and (iv) (d) (ii) and (iii)

Harshit Singh , 3 Years ago

Grade 12th pass