calculate molar mass of C2H2
Molar mass of C=12g
Molar mass of H = 2g
Now
Molar mass of C2H2= 2 (molar mass of C)+ 2(molar mass of H)
= 2x12+2x1= 24+2 =26g.
Calculate molar mass of CO(NO3)2.6H2O