13 th group elements (p-block) practice · Mixed difficulty

Hardest element of III A group of gp.13 is:

Aluminium becomes passive in nitric acid because it:

Colemanite is an important mineral of boron. It is represented $\mathrm{Ca}_2 \mathrm{~B}_x \mathrm{O}_{11} \cdot 6 \mathrm{H}_2 \mathrm{O}$. What is the value of $x$ ?

In diborane, the banana bond is formed between

Diborane $({B_2}{H_6})$ reacts independently with ${O_2}$ and ${H_2}O$ to produce, respectively.

Boron compound behave as Lewis acids because of their

$\mathrm{BX}_3+\mathrm{NH}_3 \stackrel{\text { R.T. }}{\longrightarrow} \mathrm{BX}_3 \cdot \mathrm{NH}_3+$ Heat of adduct formation $(\Delta \mathrm{H}).$ The numerical value of $\Delta \mathrm{H}$ is found to be maximum for:

Which is used as antiseptic for eyes

Aluminium appears like gold when it is mixed with:

Due to inert pair effect in 13th group

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) In $Tl{I_3}$, isomorphous to $Cs{I_3}$, the metal is present in + 1 oxidation state.
Reason (R) $Tl$ metal has fourteen $f -$electrons in the electronic configuration.
In the light of the above statements, choose the most appropriate answer from the options given below.

Assertion (A): $\mathrm{HBF}_4$ is a very strong acid.

Reason $(\mathbf{R}): \mathrm{B}(\mathrm{OH})_3$ behaves as an acid in the following reaction :
$\mathrm{B}(\mathrm{OH})_3+4 \mathrm{HF} \longrightarrow \mathrm{H}_3 \mathrm{O}^{+}+\left[\mathrm{BF}_4 \right]^{-}+2 \mathrm{H}_2 \mathrm{O}.$

Which is electron deficient compound?

Assertion: Boron is a good conductor of electricity.

Reason: Boron has a low ionization energy and a high electron affinity.

The ratio of $\mathrm{F}{\mathrm{e}_2}{\mathrm{O}_3}$ and Al, in thermite is

Which of the following is most abundant in the earth crust?

Alums are used for

Which of the following statement(s) is/are incorrect ?

(i) Trichlorides on hydrolysis in water form tetrahedral $\left[\mathrm{M}(\mathrm{OH})_4\right]^{-}$species.

(ii) Hybridisation state of metal in tetrahedral species is $\mathrm{sp}^3$.

(iii) Aluminium chloride in acidified aqueous solution forms $\left[\mathrm{Al}(\mathrm{OH})_4\right]^{-}$ion.

The 13th group element which has the least melting point is

Assertion (A) : ${AlCl}_3$ forms dimer ${Al}_2 {Cl}_6$ but is dissolves in ${H}_2 {O}$ forming $\left[{Al}\left({H}_2 {O}\right)_6\right]^{3+}$ and ${Cl}^{-}$ions.

Reason (R) : Aqueous solution of ${AlCl}_3$ is acidic due to hydrolysis.

A non-metallic element of group 13 , used in making bullet proof vests is extremely hard solid of black colour. It can exist in many allotropic forms and has unusually high melting point. Its trifluoride acts as

Which one of the following compounds, is not a protonic acid?

Which of the following ions do not exist?
$\begin{array}{cccccccccccccccccccc} {{\text{i}}.\,\,\,{B^{3 + }}}&{{\text{ii}}.\,\,\,A{l^{ + 3}}}&{{\text{iii}}.\,\,\,G{a^{3 + }}}&{{\text{iv}}.\,\,\,T{l^{3 + }}} \end{array}$

Boric acid is prepared from borax by the action of:

In Gold Schmidt reaction, certain metallic oxides are reduced to the metallic state by-heating with:

Assertion (A) : ${B}_2 {Cl}_4, {GaCl}_2, {GaS}$ are diamagnetic.

Reason (R) : They show +2 oxidation state.

Which of the following is non-metallic?

Alum is not used:

Oxidation state of boron in magnesium boride $\left( {M{g_3}{B_2}} \right)$

A compound $X$, of boron reacts with $\mathrm{NH}_3$ on heating to give another compound $Y$, which is called inorganic benzene. The compound $X$ can be prepared by treating $\mathrm{BF}_3$ with lithium aluminium hydride. The compounds $X$ and $Y$ are represented by the formulae