Hello Aspirant,

C4H10 has two isomers

1.CH3-CH2-CH2-CH3 n-butane and

2.CH3-CH(CH3)-CH3 isobutane

1 on photochemical chlorination  will give

CH3-CH(Cl)-CH2-CH3 and

ClCH2-CH2-CH2-CH3

2 on chlorination will give

ClCH2-CH(CH3)-CH3 and

CH3-C(Cl)(CH3)-CH3

C4H10 will not give monochlorinated products.

However an isomer of pentane I.e., neo-pentane will give a monochlorinated product.

C(CH3)4 + Cl2/hv ---------› C(CH2Cl)(CH3)3

1-chloro-2,2-dimethyl butane

Neopentane will give a monochlorinated product because it has 4 methyl groups attached to it.

I hope it helps.

Thank you