CGPET 2018 Solved Paper

Formula of butane diol is C4H10O2.
∴ It's molecular mass =(4×12)+(10×1)+(2×16)=90
Given, mass of butane diol (w)=0.9g
∴n=

w

m

=

0.9

90

=0.01mol
where, n= number of moles
At STP, n=

Volume of gas (V)

22.4(L)

∴V=n×22.4L
or V=n×22400(mL)
or V=0.01×22400 or V=224mL
∴(1) is the correct statement.
2. When 2 -iodobutane reacts with NaI, it gives alkyl di-iodide in which iodine atoms are attached with the 2° -carbon. Thus, due to steric-hindrance it will undergo SN1 reaction. Hence, we get racemic mixture.
∴ Statement (2) is correct.
3. Structure of 2 -methyl butane is as follows:

1

C

H3−

2 C |

CH3

H−

3

C

H2−

4

C

H3
∵ It has two similar groups, present on C2 carbon atom. It is not optically active.
∴ Statement (3) is wrong.
4. C4H8 does not show 7 -isomers, as it has only four carbon atoms.
∴ Statement (4) is wrong.
∴ Option (c) is the correct option.