In the chemical reaction, 

Cl₂ + H₂S → 2HCl + S.

The oxidation number of sulphur changes from

• 0 to 2

• 2 to 0

• -2 to 0

• -2 to -1

What is the oxidation number of chromium in potassium dichromate?

• +2

• +3

• +6

• -4

In the reaction,

3Mg + N₂ → Mg₃N₂

• magnesium is reduced

• magnesium is oxidised

• nitrogen is oxidised

• None of the above

With the increase in atomic weights, melting points of the alkali metals

• increase

• decrease

• remain constant

• do not show definite trend

Alkali metals in each period have

• smallest size

• owest ionization potential

• highest ionisation potential

• highest electronegativity

In potassium manganate, the oxidation state of manganese is

• +5

• +6

• +7

• +8

37.

Ferric ion forms a Prussian blue coloured precipitate due to formation of

• K₄[Fe(CN)₆]

• Fe₄[Fe(CN)₆]₃

• Fe(CNS)₃

• K₃[Fe(CN)₆]

The reactivity of the alkali metal sodium with water, is made use of

• in drying of alcohols

• in drying of benzene

• in drying of organic amines

• as a general drying agent

The bleaching action of the bleaching powder is due to the liberation of

• chlorine

• molecular oxygen

• nascent oxygen

• calcium carbonate

Al³⁺, Fe³⁺, Zn²⁺ and Ni²⁺ ions are present in an acidic solution. Excess of ammonium chloride solution followed by addition of ammonium hydroxide solution. The available precipitate will contain

• Zn(OH)₂ and Ni(OH)₂

• Al(OH)₂ and Fe(OH)₃

• Zn(OH)₂ and Al(OH)₃

• Ni(OH)₂ and Fe(OH)₃