Ans: (a)
296. Which one of the following is not radioactive?
     (a) Astatine
     (b) Francium
     (c) Tritium
     (d) Zirconium
Ans: (d)
297. Consider the following statements: Hard water is not suitable for
     1) drinking
     2) washing clothes with soap
     3) use in boilers
     4) irrigating crops
     Which of these statements are correct?
     (a) 1 and 3
     (b) 2 and 3
     (c) 1, 2 and 4
     (d) 1, 2, 3 and 4
Ans: (d)
298. Which one of the following is present in the largest amount in terms of per cent by mass in the earth"s crust?
     (a) Silicon
     (b) Oxygen
     (c) Carbon
     (d) Calcium
Ans: (b)
299. When ants bite, they inject
     (a) glacial acetic acid
     (b) methanol
     (c) formic acid
     (d) stearic acid
Ans: (c)
300. Vinegar is an aqueous solution of
     (a) oxalic acid
     (b) citric acid
     (c) acetic acid
     (d) hydrochloric acid
Ans: (c)