Identify the $-I$ effect causing group from the following.

Arrange the following according to the instructions:
$(i)$ Arrange in descending order of acidic strength:
$CH_3COOH, (CH_3)_3CCOOH, (CH_3)_2CHCOOH, CH_3CH_2COOH$
(ii) Arrange in descending order of stability:
$\stackrel{+}{CH}_3, (CH_3)_3\stackrel{+}{C}, CH_3CH_2^+, (CH_3)_2\stackrel{+}{CH}$
(iii) Arrange in increasing order of acidic strength:
$CCl_3COOH, CH_3COOH, CHCl_2COOH, CH_2ClCOOH$
(iv) Arrange in increasing order of stability:
$(a)$ $CH_3CH=CH-CHO$
$(b)$ $CH_3\stackrel{+}{CH}-CH=C-O:^-$
$(c)$ $\stackrel{+}{CH}_2-CH=CH-C=O$
$(v)$ Arrange in decreasing order of stability:
$(I)$ $CH_2=CH-CHO$
$(II)$ $\stackrel{+}{CH}_2-CH=C-H$ (with $O^-$)
$(III)$ $:CH_2-CH=C-H$ (with $O^-$)

The functional group that shows negative resonance effect ($-R$ effect) 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 the compound given below,the correct order of the acidity of the positions $(X)$,$(Y)$ and $(Z)$ is:

State True or False for the following statements regarding the $-NO_2$ group in nitrobenzene:
$(i)$ In resonance,it acts as an electron-donating group,and in the inductive effect,it acts as an electron-attracting group.
$(ii)$ It acts as an electron-donating group in both resonance and the inductive effect.
$(iii)$ It acts as an electron-attracting group in both resonance and the inductive effect.
$(iv)$ It acts as an electron-attracting group in resonance and an electron-donating group in the inductive effect.