In a given sample

In the first sample:

9g of hydrogen and 42g of nitrogen are present. According to the law of definite proportion, hydrogen and nitrogen are present in the ratio of 9:42 i.e., 3:14

In the second sample:

It is given that 5g of hydrogen is present along with nitrogen.

According to the law of constant proportion the second sample

must also contain hydrogen and nitrogen in 3:14 ratio.

⇒

⇒ 14 × 5 = 3 × amt. of nitrogen

⇒ Amount of nitrogen = 70/3

⇒ Amount of nitrogen = 23.3g

Thus, the amount of nitrogen in the second sample is 23.3g.