Question

Which of the following reactions if carried out to completion at constant temperature and volume would decrease the pressure in the reaction chamber to 2/3 of the original value?

a.

N2(g) + 3H2(g) → 2NH3(g)

b.

2NO2Cl(g) → 2NO2(g) + Cl2(g)

c.

2NO2(g) → N2O4(g)

d.

2SO2(g) + O2(g) → 2SO3(g)

e.

C2H2(g) + 2H2(g) → C2H6(g)

Answer 1

Pressure should become 2/3 of original value

So,

final mol of gas= (2/3)*initial mol of gas

a)

final mol of gas = 2

initial mol of gas = 1+3 = 4

final mol of gas / initial mol of gas = 2/4 = 1/2

b)

final mol of gas = 2+1 = 3

initial mol of gas = 2

final mol of gas / initial mol of gas = 3/2

c)

final mol of gas = 1

initial mol of gas = 2

final mol of gas / initial mol of gas = 1/2

d)

final mol of gas = 2

initial mol of gas = 2+1 = 3

final mol of gas / initial mol of gas = 2/3

e)

final mol of gas = 1

initial mol of gas = 1+2 = 3

final mol of gas / initial mol of gas = 1/3

Answer: d