When \( 5.1 \, \text{g} \) of solid \( \mathrm{NH}_4\mathrm{HS} \) is introduced into a two litre evacuated flask at \( 27^{\circ}\text{C} \), \( 20\% \) of the solid decomposes into gaseous ammonia and hydrogen sulphide. The \( K_p \) for the reaction at \( 27^{\circ}\text{C} \) is \( x \times 10^{-2} \). The value of \( x \) is _______. (Integer answer)
[Given : \( R = 0.082 \, \text{L atm K}^{-1} \text{mol}^{-1} \)]
