Question

1. Tungsten carbide (WC), used in making tools and jewelries, is produced by the reaction of tungsten hexachloride (WCl6), H2 and CH4 at 670℃.

WCl6 + H2 + CH4 WC + 6HCl

If 23.5 g WCl6 reacts with excess H2 and CH4, and 10.8 g WC are recovered, what is the percent yield?

Answer 1

Taking W=183.84 Cl=35.453 C=12.0107

WCl₆= 183.84+ (35.453×6)= 396.558g

WC= 183.84+ 12.0107

= 195.8507g

396.558 of WCl₆ yields 195.8507 of WCl₆

23.5g of WCl₆ in the same proportion should yield

$=\frac{23.5}{396.558}×195.8507=11.6061g$

of WCl₆

Actual yield given = 10.8g

$\%$ yield $=\frac{Actual \>yield}{Theoretical \> value}×100\%$

$=\frac{10.8}{11.6061}×100\%=93.06\%$