<u>Answer:</u> The value of  is coming out to be 0.412
 is coming out to be 0.412
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
 .....(1)
      .....(1)
- <u>For  </u> </u>
Given mass of  = 1.00 kg = 1000 g   (Conversion factor: 1 kg = 1000 g)
 = 1.00 kg = 1000 g   (Conversion factor: 1 kg = 1000 g)
Molar mass of  = 339.7 g/mol
 = 339.7 g/mol
Putting values in equation 1, we get:

Given mass of hydrogen gas = 10.0 g
Molar mass of hydrogen gas = 2 g/mol
Putting values in equation 1, we get:

- <u>For hydrogen sulfide:</u>
Given mass of hydrogen sulfide = 72.6 g
Molar mass of hydrogen sulfide = 34 g/mol
Putting values in equation 1, we get:

The chemical equation for the reaction of antimony sulfide and hydrogen gas follows:
                   
Initial:            2.944      5
At eqllm:      2.944-x     5-3x         2x        3x
We are given:
Equilibrium moles of hydrogen sulfide = 2.135 moles
Calculating for 'x', we get:

Equilibrium moles of hydrogen gas = (5 - 3x) = (5 - 3(0.712)) = 2.868 moles
Volume of the container = 25.0 L
Molarity of a solution is calculated by using the formula:

The expression of  for above equation, we get:
 for above equation, we get:
![K_c=\frac{[H_2S]^3}{[H_2]^3}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BH_2S%5D%5E3%7D%7B%5BH_2%5D%5E3%7D)
The concentration of solids and liquids are not taken in the expression of equilibrium constant.

Hence, the value of  is coming out to be 0.412
 is coming out to be 0.412