Identify the functional group that has electron donating inductive effect.

Which of the following groups as $X$ will decrease the $pKa$ value of the given compound?

How is the movement of electrons represented in organic reaction mechanisms?

The decreasing order of acidic nature of the following compounds is

Explain the terms Inductive and Electromeric effects. Which electron displacement effect explains the following correct orders of acidity of the carboxylic acids?
$(a)$ $Cl_3CCOOH > Cl_2CHCOOH > ClCH_2COOH$
$(b)$ $CH_3CH_2COOH > (CH_3)_2CHCOOH > (CH_3)_3C \cdot COOH$

In which of the following compounds is the hyperconjugation effect not present?