Chemical Reactions Of Alcohols Phenols And Ethers

• NaNH₂ acts as a strong base and is commonly used for the double elimination of geminal or vicinal dihalides to yield alkynes. This process involves the removal of two halogen atoms from adjacent carbon atoms, resulting in the formation of a carbon-carbon triple bond (alkyne)
• Lindlar's catalyst, which consists of palladium on calcium carbonate (Pd-C) with quinoline, is a selective catalyst used to reduce alkynes to alkenes. Unlike typical hydrogenation reactions, Lindlar's catalyst allows for the reduction of alkynes to alkenes without further reduction to alkanes. This selective reduction is useful in organic synthesis for controlling the outcome of reactions involving alkynes.

→ P may be → H₂/Pd, ethanol; Sn/HCl

→ R may be → NaNO₂/HCl; HNO₂

→ U may be → (i) H₃PO₂, (ii) KMnO₄ – KOH, Δ or (i) CH₃ – CH₂ – OH, (ii) KMnO₄ – KOH, Δ
So the correct options are A,B and C.