NTA Abhyas NEET2020ChemistryChemical EquilibriumPractice
When 3.06 g of solid NH 4 H S is introduced into a two litre evacuated flask at 27 ° C , 30 % of the solid decomposes into gaseous ammonia and hydrogen sulphide. The values of K c and K p for the reaction at 27 ° C respectively will be:
Options
- A8.1 × 10 − 4 and 3.9 × 10 − 2
- B0.8 × 10 − 5 and 4.9 × 10 − 5
- C9.1 × 10 − 3 and 4.9 × 10 − 3
- D8.1 × 10 − 5 and 4.9 × 10 − 2
Correct answer
D. 8.1 × 10 − 5 and 4.9 × 10 − 2
Step-by-step solution
NH 4 H S ( s ) ⇌ N H 3 ( g ) + H 2 S ( g ) Initial moles 3.06 51 0 0 Moles at eq. 3.06 51 × 70 100 3.06 51 × 30 100 3.06 51 × 30 100 Given: V = 2 litre, T = 300K, Δ n = 2 − 0 = 2 ∴ K c = [ N H 3 ] [ H 2 S ] K c = 3.06 × 30 51 × 100 × 2 × 3.06 × 30 51 × 100 × 2 = 8 . 1 × 1 0 - 5 M 2 Also, K p = K c ( RT ) Δ n = 8.1 × 10 − 5 ( 0.082 × 300 ) 2 = 4.90 × 10 − 2 atm 2 Addition of more NH 4 H S on this equilibrium will cause no effect because concentration of NH 4 H S is not involved in formula of K p and K c .