Which of the following molecule is linear:(A) S{{O}_{2}}(B) N{{O}_{2}}^{+}(C) N{{O}_{2}}(D) SC{{l}_{2}}

To determine which of the given molecules is linear, we need to consider their molecular geometry and the arrangement of atoms.

(A) SO2 (Sulfur Dioxide): SO2 is a bent or V-shaped molecule. It has a bond angle of approximately 119 degrees, which makes it non-linear.

(B) NO2+ (Nitronium ion): NO2+ is a linear molecule. It consists of two oxygen atoms bonded to a central nitrogen atom with a linear arrangement.

(C) NO2 (Nitrogen Dioxide): NO2 is a bent or V-shaped molecule, similar to SO2. It is not linear and has a bond angle of approximately 134 degrees.

(D) SCl2 (Sulfur Dichloride): SCl2 is a linear molecule. It consists of a central sulfur atom bonded to two chlorine atoms with a linear arrangement.

So, the linear molecule among the options is (B) NO2+.