The questions involve ordering the answer either from lower to higher acidity or basicity include the nucleophilic and electrophilec site of actions.
Q5- D is the correct answer , beacuse generally any hydrogen attached to high electronegative atom, is considered acidic hydrogen and so oxygen is more electronegative than carbon so hydrogen attached to carbon is lowest in acidity. Regarding hydrogen number a and c, both of them attached to oxygen but the negative charge in carboxyl group is more stable than the negative charge on oxide one because of the resonance effect.
Q-6 C is the correct answer, the rule usually says that SP hybridization> SP2 hybridization>SP3 hybridization in acidity because the higher percentage of S orbital character in each of them
Q-7 B is the correct answer, A is lowest in acidity because all hydrogens are attached to carbon which is low in electronegativity so will not withdraw the electrons from hydrogen to set the hydrogen proton free, B and D are higher in the acidity than C because of the resonance action ...