Which of the following is/are incorrect statement (s):
(I) `CHCl_(3)` is less acidic than `CHF_(3)`
(II) Dipole moment of chlorobenzene is more than chlorocyclohexane
(III) Dipole moment of fluoromethane is more than chloromethane
(IV) `NH_(2)NH_(2).HCl` show positive test for nitrogen in lassaigne's test
(V) Dipole moment of difluoromethane is more than dichloromethane,

Options

A. I only
B. II only
C. I,II,III only
D. I,II,III,IV and V

Answer

C

Explanation

`CHCl_(3)tobar"CC"l_(3)+H^(+)`
`CHF_(3)tobarCF_(3)+H^(+)`
`impliesbar"CC"l_(3)` is more stable than `barCF_(3)` due to `P_(pi)-d_(pi)` bonding hence `CHCl_(3)` is more acidic, not `CHF_(3)` so, (I) incorrect.
`implies` in chlorobenzene `C-Cl` bond length decreases due to resonance and hence its dipole moment is lesser than chlorocyclohexane ii is also incorrect.
`implies` Dipole moment of fluoromethane is lesser than chloromethane due to very small size of `F`. ii is also incorrect.
`implies` Carbon and nitrogen atom containing organic compound gives positive test for nitrogen in lassaigne's test
`implies` Diple moment of difluoromethane is more than dichloromethane.
`CH_(2)F_(2) CH_(2)Cl_(2)`
`mu=1.97D 1.60D`