0.037g of an alcohol, R-OH was added to `CH_(3)MgBr` and the gas evolved measured 11.2 mL at STP. The Molecular mass of R-OH will be .

Options

A. 47
B. 79
C. 74
D. 77

Answer

C

Explanation

[Hint]
`{:(R-OH,+,CH_(3)MgBr,rarr,CH_(4),+,Mg(Br)OR),(1 mol,,,,1 mol,,),(,,,,or,,),(,,,,22400 "mL at STP",,):}` ltBRgt 11.2 Ml `ch_(4)` at STP is formed by 0.037 g ROH
`:. ` 22400 mL `CH_(4)` at STP will be formed by
`(0.037)/(11.2)xx22400`g ROH
=74 g ROH
`:. `Molar mass of R-OH `=74`