The method used to remove the temporary hardness of water is-

1. Synthetic resins method

2. Calgon's method

3. Clark's method

4. Ion-exchange method

The ease of adsorption of the hydrated alkali metal ions on ion-exchange resins follows the order:

1. $L{i}^{+}<K^{+}<N{a}^{+}<R{b}^{+}$

2. $R{b}^{+}<K^{+}<N{a}^{+}<L{i}^{+}$

3. $K^{+}<N{a}^{+}<R{b}^{+}<L{i}^{+}$

4. $N{a}^{+}<L{i}^{+}<K^{+}<R{b}^{+}$

The reaction of aqueous KMnO₄ with H₂O₂ in acidic condition gives:
1. $M{n}^{4+}$ $and$ $O_2$
2. $M{n}^{2+}$ $and$ $O_2$
3. $M{n}^{2+}$ $and$ $O_3$
4. $M{n}^{4+}$ $and$ $Mn{O}_2$

An incorrect statement among the following regarding hydrogen is:
 

If the molality of the dilute solution is doubled, the value of molal depression constant (K_f) will be-
1. Halved
2. Tripled
3. Unchanged
4. Doubled

Match the following and identify the correct option

Some statements about water are given below:
 

Which of the above statements are correct?

1. (a), (b), and (c)

2. (b) and (c)

3. (a) and (c)

4. (a) and (b)

The pair that on reaction will not evolve $H_2$ gas is  

1.  Copper and HCl (aqueous)
2.  Iron and steam
3.  Iron and $H_{2}S{O}_4$ (aqueous)
4.  Sodium and ethyl alcohol

 $H_2{O}_{\mathrm{2 }}$on oxidation gives:

1. $O^{-2}$

2. $O{H}^{-}$

3. $O_2^{-}$

4. $O_2$

Pure water can be obtained from sea water by:

1.  Centrifugation
2.  Plasmolysis
3.  Reverse osmosis
4.  Sedimentation