The alkene which gives 4,4-dimethylpentan-2-one on reductive ozonolysis is
Ozonolysis of alkenes involves the addition of an ozone molecule to an alkene, to form an ozonide. Formed ozonide undergoes cleavage by Zn/H2O to give smaller oxidised product.
Compound (a) undergo ozonolysis to give formaldehyde and 4, 4-dimethyl pentan-2-one.