The parent chain is butane (4 carbons). Numbering from the end nearest to substituent gives Br at position 2. IUPAC name is 2-bromobutane. Option D is a common name.

Tollens test is positive for aldehydes. Propanal (CH₃CH₂CHO) is an aldehyde and gets oxidized to carboxylic acid, reducing Ag⁺ to Ag (silver mirror). Acetone is a ketone, ether and alcohol do not give positive test.

tert-Butyl bromide is a tertiary alkyl halide. Tertiary substrates preferentially undergo SN1 mechanism due to stable tertiary carbocation formation. SN2 is hindered by steric effects.

But-2-ene (CH₃-CH=CH-CH₃) on ozonolysis gives two identical fragments, each being acetaldehyde (CH₃CHO). The double bond cleaves symmetrically.

Tertiary carbocation (CH3)3C+ is most stable due to maximum hyperconjugation and inductive stabilization from three alkyl groups.

Williamson ether synthesis uses SN2 reaction between alkoxide (R-O-) and alkyl halide (R'-X) to form R-O-R'.

NO2+ (nitronium ion) is an electrophile with positive charge, not a nucleophile. All others have lone pairs or negative charge.

Acetone (CH3-CO-CH3) has α-hydrogen atoms and can exist in equilibrium between keto and enol forms.

Addition to alkenes follows electrophilic addition mechanism with carbocation formation, leading to Markovnikov's product.

Chromic acid oxidizes primary alcohols to carboxylic acids. The aldehyde is an intermediate which is further oxidized.