Solve this:
Q.18. 3 mol of ammonia contains:
(A) 18 gm of hydrogen
(B) 42 gm of nitrogen
(C) both
(D) None

THE ANSWER FOR THIS QUESTION IS (B)-42 GRAMS OF NITROGEN.
SEE,
THE GIVEN REACTION IS AS FOLLOWS=
     (1) NH3 ------>   (1)N  +  (3)H
1 MOLE OF AMMONIA REACTS WITH 1 MOLE OF NITROGEN PLUS 3 MOLES OF HYDROGEN

=>3 MOLES OF AMMONIA CONTAIN 3 MOLES OF NITROGEN.
=> 3 MOLES OF NITROGEN = 3XATOMIC MASS OF N
                                                   = 3 X 14 = 42 g OF NITROGEN.
=> 3 MOLES OF AMMONIA REACTS WITH 9 MOLES OF HYDROGEN
                                                   = 9 X ATOMIC MASS OF HYDROGEN
                                                   = 9 X 1 = 9 g OF HYDROGEN