61. Which of the following metals remain in liquid for under normal conditions?
A. Radium
B. Zinc
C. Uranium
D. Mercury
62. Potassium Permanganate is used for purifying drinking water, because
A. it is a sterilising agent
B. it dissolves the impurities of water
C. it is a reducing agent
D. it is an oxidising agent
63. Which of the following is an element?
A. Ruby
B. Sapphire
C. Emerald
D. Diamond