For the equilibrium: `CaCO_(3(s)) iff CaO_((s)) + CO_(2(g)) , K_p = 1.64` atm at 1000 K, 50 g of `CaCO_3` in a 10 litre closed vessel is heated to 1000 K. Percentage of `ĆaCO_3` that remains unreacted at equilibrium is (Given R=0.082 L atm `K^(-1) "mol"^(-1)`).

Options

A. 40
B. 50
C. 60
D. 20

Answer

C

Explanation

`CaCO_3 iff CaO + CO_2`
`Kp = pCO_2`
No. of moles =n
`1.64 xx 10 = 0.082 xx 1000 xx n`
`n=(1.64 xx 10)/(0.082 xx 1000)=0.2`
`:.` No. of moles `CO_2 = 0.2`
50g of `CaCO_3 = 0.5` moles of `CaCO_3` gives 0.2 moles of `CO_2`
`implies` percentage of `CaCO_3` unreacted = 0.3 mole = 60%