Zn and Cd metals do not show variable valency because :

1. They have only two electrons in the outermost subshells

2. Their d-subshells are completely filled

3. Their d-subshells are partially filled

4. They are relatively soft metals

Which of the following graph is correct representation between atomic number (Z) and magnetic moment of d-block elements? [Outer electronic configuration : (n-1)d^xns^{1 or 2}]

Which of the following metal is expected to have the highest third ionization enthalpy?

1. Cr(Z = 24)

2. V(Z = 23)

3. Mn(Z = 25)

4. Fe(Z = 26)

An orange-coloured solution of K₂Cr₂O₇ is acidified with H₂SO₄ and treated with H₂O₂ resulting in a blue coloured solution. The blue colour is due to the formation of

$\mathrm{Fe}+{\mathrm{H}}_2\mathrm{O}\stackrel{1023-1073\mathrm{K}}{\to } \mathrm{Product}$
$\left(\mathrm{Steam}\right)$
$\mathrm{Product} \mathrm{formed} \mathrm{is}$
$1. \mathrm{FeO}+{\mathrm{H}}_2$

2. ${\mathrm{Fe}}_2{\mathrm{O}}_3+{\mathrm{H}}_2\mathrm{O}$

3. ${\mathrm{Fe}}_2{\mathrm{O}}_3+{\mathrm{H}}_2$

4. ${\mathrm{Fe}}_3{\mathrm{O}}_4+{\mathrm{H}}_2$

Which of the following gives $H_{2 }when reacts with dil. HN{O}_3?$

1. Mn

2. Fe

3. Ni

4. Zn

A pair of metals which dissolves in sodium hydroxide solution is

When ${\mathrm{I}}^{-}$ is oxidised by ${\mathrm{MnO}}_4^{-}$ in alkaline medium, ${\mathrm{I}}^{-}$ converts into-

1. ${\mathrm{IO}}_3^{-}$

2. ${\mathrm{I}}_2$

3. ${\mathrm{IO}}_4^{-}$

4. ${\mathrm{IO}}^{-}$

Which one of the following statements related to lanthanum is incorrect?

1.  Europium shows +2 oxidation state.

2.  The basicity decreases as the ionic radius decreases from pr to Lu.

3.  All the lanthanoids are much more reactive than aluminum.

4.  Ce⁺⁴ solution are widely used as the oxidizing agents in volumetric analysis.