Consider the following sequence of reactions.

The percentage of nitrogen in the yellow product (X) formed is _______ %. (Nearest Integer)
(Given Molar mass in g mol$$^{-1}$$ H:1, C:12, N:14)

When diazoaminobenzene is warmed to $40\text{-}45^\circ\text{C}$ in the presence of hydrochloric acid ($\text{HCl}$) and excess aniline, it rearranges to form p-aminoazobenzene (a well-known yellow dye).

The product formed from the reaction 

Using the provided atomic masses ($$\text{C} = 12$, $\text{H} = 1$, $\text{N} = 14$$):

$$\text{Molar Mass} = (12 \times 12) + (11 \times 1) + (3 \times 14)$$
$$\text{Molar Mass} = 144 + 11 + 42 = 197\text{ g mol}^{-1}$$

The total mass contributed by the 3 nitrogen atoms in one mole of the compound is:

$$\text{Mass of Nitrogen} = 3 \times 14 = 42\text{ g mol}^{-1}$$

Now, find the mass percentage:

$$\text{Percentage of Nitrogen} = \left( \frac{42}{197} \right) \times 100 \approx 21.32\%$$

Rounding to the nearest integer gives 21%.