A compound possessing `alpha`-hydrogen atom, in the presence of dilute alkali forms `beta`-hydroxy aldehyde. This product on heating with dilute acid forms an unsaturated crotonaldehyde. The compound is

The products formed when metals react with dilute acids are:

Phenol reacts with HCHO in presence of dilute acid forms _____.

When two molecules of acetaldehyde condense in the presence of a dilute alkali , it forms :

The compound that gives hydrogen peroxide on treatment with a dilute cold acid is:

A halogen compound on hydrolysis with dilute alkali followed by acidification gives acetic acid. The compound is :

An unknown aldehyde A on reaction with alkali gives a beta - hydroxy aldehyd, which loses water to form an unsaturated aldehyde, But-2-enal. Another aldehyde 'B' disproporationation reaction in the presence of conc, alkali to form products C and D. C is an aryl alcohol wit the formula ( C_(2)H_(8)) (1) Identify A and B. (ii) Write the sequence of reactions involved. (iii) Name the product, when B reacts with Zn amalgam and hydrochloric acid.

An unknown aldehyde 'A' on reacting with alkali gives a beta hydroxy aldehyde, which losses water to form an unsaturated aldehyde, but-2-enal. Another aldehyde 'B' undergoes disproportionation reaction in the presence of conc alkali to form products 'C' and 'D'. 'C' is an aryl alcohol with formula C_7H_8O : Identify A and B.