Question

5 moles of $\mathrm { SO } _ { 2 }$and 5 moles of $\mathrm { O } _ { 2 }$ react in a closed vessel. At equilibrium 60% of the $\mathrm { SO } _ { 2 }$is consumed. The total number of gaseous moles

( and $\mathrm { SO } _ { 3 }$ ) in the vessel is.

• A. $5.1$
• B. $3.9$
• C. $10.5$
• D. $8.5$

Answer 1

Answer: (D)

$8.5$

Answer 2

: $2 \mathrm { SO } _ { 2 }$ + $\mathrm { O } _ { 2 }$ $2 \mathrm { SO } _ { 3 }$

Initial moles 5 5 0

At equilibrium 5 – 3 $5 - \frac { 3 } { 2 }$ $3 \left( 5 \times \frac { 60 } { 100 } = 3 \right)$

Total number of moles in the vessel $= 2 + 3.5 + 3 = 8.5$