Assertion : K₂Cr₂O₇ is used as primary standard in volumetric analysis.

Reason : It has a good solubility in water.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false

• If both assertion and reason are false.

Assertion: Chemistry of actinoids is more complicated than lanthanoids.

Reason: Actinoid elements are radioactive.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

263.

Which of the following will form a colourless complex ?

• Ni²⁺

• Cu⁺

• Ti²⁺

• Fe³⁺

Which belongs to the actinide series ?

• Ce

• Cf

• Ca

• Cs

The group of elements in which the differentiating electrons enters in the antepenultimate shell of atoms are called :

• f - block elements

• p - block elements

• s - block elements

• d - block elements

Brass, bronze and german silver have one common metal . This is :

• Zn

• Fe

• Al

• Cu

When calomel is treated with ammonium hydroxide, a black substance is formed. The black substance is

• Hg + HgO

• HgO.HgCl₂

• H₂N-Hg-Cl+Hg

• Hg(NH₂)₂ + HgO

Which is not stable under ambient condition?

• ${\mathrm{TiO}}_{2, }{\mathrm{Ti}}^{+4}$

• $\mathrm{VO}, {\mathrm{V}}^{+4}$

• ${\mathrm{VO}}_{2, }{\mathrm{V}}^{+5}$

• ${\mathrm{Cu}}_2\mathrm{O}, {\mathrm{Cu}}^{+2}$

Magnetic moment of Cr²⁺ is nearest to

• Fe²⁺

• Mn²⁺

• Co²⁺

• Ni²⁺

Assertion : Ce⁴⁺ is used as an oxidising agent in volumetric analysis.

Reason : Ce⁴⁺has the tendency of attaining + 3 oxidation state

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.