Metals and Non-metals
NCERT Exemplar Problems
MCQ Part 3
Question 19: Generally, non-metals are not lustrous. Which of the following nonmetal is lustrous?
Answer: (d) Iodine
Question 20: Which one of the following four metals would be displaced from the solution of its salts by other three metals?
Answer: (b) Ag
Explanation: In the reactivity series of metals, silver is at the bottom among given four metals.
Question 21: 2 mL each of concentrated HCl, HNO3 and a mixture of concentrated HCl and concentrated HNO3 in the ratio of 3 : 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C respectively. The metal could be
Answer: (b) Au
Explanation: A mixture of HCl and HNO3 in 3:1 ratio is called Aqua regia, which dissolves gold and silver.
Question 22: An alloy is
- an element
- a compound
- a homogeneous mixture
- a heterogeneous mixture
Answer: (c) A homogeneous mixture
Question 23: An electrolytic cell consists of
- positively charged cathode
- negatively charged anode
- positively charged anode
- negatively charged cathode
- (i) and (ii)
- (iii) and (iv)
- (i) and (iii)
- (ii) ad (iv)
Answer: (b) (iii) and (iv)
Question 24: During electrolytic refining of zinc, it gets
- deposited on cathode
- deposited on anode
- deposited on cathode as well as anode
- remains in the solution
Answer: (a) Deposited on cathode
Question 25: An element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following
Answer: (b) Na
Question 26: Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among the following alloys contain non-metal as one of its constituents?
Answer: (d) Steel
Explanation: Steel is a mixture of iron (metal) and carbon (non-metal). Brass is a mixture of copper and zinc. Bronze is a mixture of copper and tin. Amalgam is a mixture of mercury and any other metal.
Question 27: Which among the following statements is incorrect for magnesium metal?
- It burns in oxygen with a dazzling white flame
- It reacts with cold water to form magnesium oxide and evolves hydrogen gas
- It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas
- It reacts with steam to form magnesium hydroxide and evolves hydrogen gas
Answer: (b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas