Aluminium becomes passive in nitric acid because it-

1. Is a noble metal

2. Forms a thin film of oxide

3. Has a positive reduction potential

4.  None of the above

The stability of the +1 oxidation state increases in the sequence:

1. Al <Ga<In<Tl

2. Tl<In<Ga<Al

3. In<Tl<Ga<Al

4. Ga<In<Al<Tl

${}_{}$
\(\mathrm{Al}_2 \mathrm{O}_3\) reacts with-

Which of the following factors is primarily responsible for the smaller atomic radius of
gallium compared to aluminium?

1. Poor shielding effect of the 2d electrons

2. Poor shielding effect of the 3d electrons

3. Poor shielding effect of the 3p electrons

4. Poor shielding effect of the 2s electrons

Borax bead test is responded by:

1.  Divalent metals

2.  Heavy metals

3.  Light metals

4.  Metal which forms coloured metaborates

Match the species given in Column I with the properties mentioned in Column II.

Codes:

Find the products formed when NaBH₄ is oxidised by I₂.

AlF₃ is soluble in HF only in the presence of KF due to the formation of:

From the following, the compound(s) that react(s) with \(\mathrm{BF}_3\) is/are :
 

Aluminium chloride in acidified aqueous solution forms a complex 'A'.
The formula of A and hybridisation state of Al in 'A' is respectively:

1. [Al(H₂O)₆]³⁺, sp³d²

2. [Al(H₂O)₄]³⁺, sp³

3. [Al(H2O)4]3+, dsp2

4. [Al(H₂O)]³⁺, d²sp³