0.70 g of mixture (NH₄)₂ SO₄ was boiled with 100 mL of 0.2 N NaOH solution till all the NH₃(g) evolved and get dissolved in solution itself. The remaining solution was diluted to 250 mL. 25 mL of this solution was neutralized using 10 mL of a 0.1 N H₂SO₄ solution. The percentage purity of the (NH₄)₂ SO sample is

(1) 94.3

(2) 50.8

(3) 47.4

(4) 79.8

A mixed solution of potassium hydroxide and sodium carbonate required 15 mL. of an N/20 HCI solution when titrated with phenolphthalein as an indicator. But the same amount of the solution when titrated with methyl orange as an indicator required 25 mL of the same acid. The amount of KOH present in the solution is

(1) 0.014g

(2) 0.14g

(3) 0.028g

(4) 1.4 g

One gm. of a metal carbonate gave 0.56 gm. of its oxide on heating. The equivalent mass of the metal is

1. 40

2. 30

3. 20

4. 10

The pair of compounds that can exist together is

1. FeCl₃, SnCl₂             

2. HgCl₂, SnCl₂

3. FeCl₂, SnCl₂             

4. FeCl₃, KI

In which of the following compounds, nitrogen exhibits highest oxidation state?

1. N₂H₄                 

2. NH₃

3. N₃H                   

4. NH₂OH

A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the

reaction which element undergoes a maximum change in the oxidation number?

1. S

2. H

3. Cl

4. C

The oxidation states of P in H₄P₂O₅, H₄P₂O₆, H₄P₂O₇, are respectively -

Oxidation numbers of P in ${\mathrm{PO}}_4^{3-}$, of S in ${\mathrm{SO}}_4^{2-}$ and that of Cr in ${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}$ are respectively,

1. +5, +6 and +6                     

2. +3, +6 and +5

3. +5, +3 and +6                     

4. -3, +6 and +6

The number of moles of MnO^-₄ required to oxidise one mole of ferrous oxalate completely in an acidic medium is-

1. 0.6 mole

2. 0.4 mole

3. 7.5 moles

4. 0.2 mole

Which one of the following orders correctly represents the increasing acid strengths of the given acids?

(1) HOCl <HOClO <HOClO₂ < HOClO₃

(2) HOClO <HOCl <HOClO₃ <HOClO₂

(3) HOClO₂ <HOClO₃ <HOClO <HOCl

(4) HOClO₃> HOClO₂ <HOClO <HOCl