The value of x : 2
Further explanation
Semi-normal Hydrochloric acid solution = 0.5 N = 0.5 M
for titration :
M₁V₁n₁=M₂V₂n₂(1=HCl,2=Na₂CO₃)
[tex]\tt 0.5\times 20\times 1=M_2\times V_2\times 2\\\\M_2V_2=5~mlmol=5.10^{-3}mol[/tex]
[tex]\tt MW=\dfrac{mass}{mol}=\dfrac{0.715}{5.10^{-3}}=143~g/mol[/tex]
MW Na₂CO₃.xH₂O=143
MW Na₂CO₃.xH₂O = MW Na₂CO₃+ MW xH₂O = 143
MW Na₂CO₃ = 106 g/mol
MW xH₂O = 18x
Equation :
[tex]\tt 106+18x=143\\\\18x=37\\\\x=\dfrac{37}{18}=2.056\approx 2[/tex]
