Question

Can I get help plz Is not D

Answer 1

Molar mass( PCl3)=31.0+35.5*3=137.5 g/mol
62.0 g PCl3*(1mol/137.5 g)    number of mol PCl3
62.0 g PCl3*(1mol/137.5 g)*(3molHCl/1 mol HCl)=1.35 mol theoretical yield of HCl

M(HCl)=1.0+35.5=36.5 g/mol
42.0 g HCl*1mol HCl/36.5 g=1.18 mol HCl actual yield

% yield =(1.18 mol HCl/1.35 mol HCl)*100%=87.4%,
Answer will be C 85.0 %

(I think difference is coming from calculations, they probably calculated this way
62.0 g PCl3*(1mol/137.5 g)*(3molHCl/1 mol HCl)*36.5gHCl/1mol HCl=
=49.35 g HCl theorethical yield

(42.0g HCl/49.37 g HCl)*100 %= 85.0 %
Yes, they calculated this way)