61 .Which one among the following is used in making gunpowder?
62 .The process of sudden cooling is known as -
63 .Hydrochloric acid is also known as
64 .The blue colour of water in the sea is due to-
65 .Neclear fission is caused by the impact of -
66 .Chromatography technique is used for the separation of
67 .In electro - refining, the pure metal is deposited on-
68 .There are only two metals that are non-silver in color, they are
69 .Who among the following proposed that atom is indivisible?
70 .Permanent hardness of water is due to the presence of
71 .The chemical used as a fixer /developer in photography
72 .The first organic compound synthesized in the laboratory was
73 .Which one is an example of Miscelles System here-
74 .Ozone depletion in the stratosphere is mainly caused by-
75 .Lemon is sour due to-