Question

If S + O2$\longrightarrow$ SO2, $\Delta$H = – 298.2 kJ mole–1

SO2 + 1/2 O2$\longrightarrow$ SO3$\Delta$H = – 98.7 kJ mole–1

SO3 + H2O $\longrightarrow$ H2SO4, $\Delta$H = – 130.2 kJ mole–1

H2 + 1/2 O2$\longrightarrow$ H2O, $\Delta$H = – 287.3 kJ mole–1

the enthalpy of formation of H2SO4 at 298 K will be –

• A. – 814.4 kJ mol–1
• B.
  • 814.4 kJ mole–1
• C. – 650.3 kJ mole–1
• D. – 433.7 kJ mole–1

Answer 1

Answer: (A)

– 814.4 kJ mol–1

Answer 2

S + O2 $\longrightarrow$ SO2 $\Delta$H = – 298.2 KJ/mole

....(1)

SO2 + $\frac{1}{2}$O2 $\longrightarrow$ SO3 $\Delta$H = – 98.7

KJ/mole ....(2)

SO3 + H2O $\longrightarrow$H2SO4 $\Delta$H = – 130.2

KJ/mole ....(3)

H2 + $\frac{1}{2}$O2 $\longrightarrow$ H2O $\Delta$H = – 287.3

KJ/mole ....(4)

Adding (1),(2),(3) and (4) we get desired equation.