Question

Nitro group in nitrobenzene is a 
1. Ortho director
2. Meta director
3. Para director
4. Ortho and Para director

Answer 1

Hint: Nitro group has chemical formula\[ - N{O_2}\]. The electron withdrawing and electron releasing nature can be on the basis of electronegativity of the elements. Electronegativity is defined as the tendency to withdraw electron clouds or electron density towards itself. A more electronegative element withdraws electronic density from a less electronegative element.

Complete solution Step by step:
Nitrobenzene can be defined as a structure of benzene with the Nitro group. The electronegativity to be compared is between carbon of benzene and Nitrogen of nitro. The electronegativity of carbon is $2.55$ and the electronegativity of nitrogen is $3.04$. As electronegativity of carbon is much more than the electronegativity of nitrogen, hence nitrogen of nitro withdraws electron density from benzene ring making it electron deficient. Oxygen attached to nitrogen makes the withdrawal of electron density making the ortho and para position electron deficient and susceptible to the attack of nucleophiles. Or in other words, the benzene ring gets electron rich at meta position thus, the electrophiles attack the meta position. But nitrobenzene being more electronegative is an electron withdrawing group that withdraws electron density.

Hence, the correct option is 4.
Nitro benzene is an ortho and para director

Note: Nitrobenzene undergoes a nucleophilic substitution reaction. The ortho and para substitution can be understood by the resonating structures which show positive charge at ortho and para position.