Consider the following reaction,

$\mathrm{Al}+\mathrm{NaOH}\to \mathrm{X}+{\mathrm{H}}_2$
${\mathrm{B}}_2{\mathrm{H}}_6 + {\mathrm{NH}}_3\to \mathrm{Y}$

X and Y in the above reaction are:

$1. \mathrm{X}= \mathrm{Al}{\left(\mathrm{OH}\right)}_2 ; \mathrm{Y} = {\mathrm{N}}_2\left[{\mathrm{BH}}_4\right]$
$2. \mathrm{X} =\mathrm{Na}\left[\mathrm{Al}{\left(\mathrm{OH}\right)}_4\right] ; \mathrm{Y} ={\mathrm{N}}_3{\mathrm{B}}_3{\mathrm{H}}_6$
$3. \mathrm{X}= \mathrm{Na}\left[\mathrm{Al}{\left(\mathrm{OH}\right)}_4\right] ; \mathrm{Y} = {\mathrm{B}}_3{\mathrm{N}}_2$
$4. \mathrm{None} \mathrm{of} \mathrm{the} \mathrm{above}$

A compound among the following that is least likely to behave as a Lewis base is:

The correct statement(s) regarding thallium is/are :

1. Thallium displays both +1, and +3 oxidation states.

2. It resembles group 1 metals in some reactions.

3. Thallium only shows a +1 oxidation state.

4. Both (1) and (2)