JEE Main 2005 Chemistry question

An amount of solid is placed in a flask already containing ammonia gas at a certain temperature and 0.50 atm. Pressure. Ammonium hydrogen sulphide decomposes to yield and gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to 0.84 atm. The equilibrium constant for decomposition at this temperature is

• (1)0.30
• (2)0.18
• (3)0.17
• (4)0.11Correct