Question

112 ml of gas is prouduced at stp by the action of 412 mg alcohol ROH with excess CH3MgI.the molecular mass of alcohol is​

Answer 1

Answer:

Hey!

This is a very well framed question but not so hard.

Explanation:

First of all the reaction will look like :-

CH3MgI   +    R-OH   --->    CH4 +    R-O-MgI

here R is any alkyl group.

but do not focus on ROH or RO MgI.....it's just to scare the child.

Actually, it is a simple question of Mole Concept.

From the reaction,

it is clear that no. of moles of gas(CH4) produced will be same as that of alcohol ROH.

So,

n = givel vol. / vol. at STP   = 112/22400  = 1/200

This implies that 1/200 moles are used in the reaction.

And it's weight is given 412 mg = 0.412g

Therefore,  (using the formula no. of moles = given wt. / molar mass)

1/200 = 0.412/Molar mass of ROH   ==>  M = 82.4g.

Thank You!

Hope u have no doubt remaining after this