71.

What is the general molecular formula of the product obtained on heating lanthaniods (Ln) with sulphur?

• LnS

• LnS₃

• Ln₃S₂

• Ln₂S₃

Choose the correct matching of transition metal ion and magnetic moment from the codes given below. (Atomic number: Ti = 22, V =23, Fe= 26)

Transition element	Magnetic moment (BM)
A. Titanium (III)	i. 4.9
B. Vanadium (II)	ii. 1.73
C. Iron (II)	iii. 3.87

• A - ii; B - iii; C - i

• A - ii; B - i; C - iii

• A - i; B - ii; C - iii

• A - i; B - iii; C - ii

The hardest lanthanide element is

• Sm

• La

• Gd

• Dy

How is sodium chromate converted into sodium dichromate in the manufacture of potassium dichromate from chromite ore?

• By the action of concentrated sulphuric acid

• By roasting with soda ash

• By the action of sodium hydroxide

• By the action of limestone

Identify the metal that forms colourless compounds.

• Iron (Z = 26)

• Chromium (Z = 24)

• Vanadium (Z=23)

• Scandium (Z =21)

Consider the following statements.

I. La(OH)₃ is the least basic among hydroxides of lanthanides.

II. Zr⁴⁺ and Hf⁴⁺ possess almost the same ionic radii.

III. Ce⁴⁺ can act as an oxidising agent.

Which of the above is/are true?

• I and III

• II and III

• II only

• I and II

Pick out the correct statement(s).

1. Manganese exhibits +7 oxidation state
2. Zinc forms coloured ions
3. [CoF₆]^3- is diamagnetic
4. Sc forms +4 oxidation state
5. Zn exhibits only +2 oxidation state

• 1 and 2

• 1 and 5

• 2 and 4

• 3 and 4

The maximum oxidation state exhibited by actinide ions is

• +5

• +4

• +7

• +8

Pick out the correct statements from the following

1.Cobalt (III) is more stable in octahedral complexes.

2. Zinc forms coloured ions or complexes.

3. Most of the d-block elements and their compounds are ferromagnetic.

4. Osmium shows (VIII) oxidation state.

5. Cobalt (II) is more stable in octahedral complex.

• 1 and 2

• 1 and 3

• 2 and 4

• 1 and 4

Which of the following statements is not correct?

• The complexes [NiCl₄]^2- and [Ni(CN)₄]^2- differ in the state of hybridization of nickel

• The complexes [NiCl₄]^2- and [Ni(CN)₄]^2- differ in the magnetic properties

• The complexes [NiCl₄]^2- and [Ni(CN)₄]^2- differ in geometry

• The complexes [NiCl₄]^2- and [Ni(CN)₄]^2- differ in primary valencies of nickel