52.
The ionisation energy of hydrogen atom in the ground state is x KJ. The energy required for an electron to jump from 2nd orbit to 3rd orbit is

53.
The major constituent of air is

54.
The main chemical constituent of clay is

55.
The mineral containing both magnesium and calcium is

56.
The metal does not give H2 on treatment with dilute HCL is

57.
The number of g-molecule of oxygen in 6.02 x 1024 CO molecules is

58.
The most extensive, commercially useful source of thorium as monazite sand occurs in India at

59.
The main active constituent of tea and coffee is

60.
The maximum number of isomers for an alkene with molecular formula C4H8 is