Write two reactions to explain amphoteric nature of water.
Water has the ability to act as an acid as well as base, i.e., it behaves as an amphoteric substance. From the Bronsted Lowry theory, it acts as an acid with $\mathrm{NH}_3$ and a base with $\mathrm{H}_2 \mathrm{~S}$.
$\begin{aligned} & \mathrm{H}_2 \mathrm{O}(l)+\mathrm{NH}_3(\mathrm{aq}) \longrightarrow \mathrm{OH}^{-}(\mathrm{aq})+\mathrm{NH}_4^{+}(\mathrm{aq}) \\ & \mathrm{H}_2 \mathrm{O}(l)+\mathrm{H}_2 \mathrm{~S}(\mathrm{aq}) \longrightarrow \mathrm{H}_3 \mathrm{O}^{+}(\mathrm{aq})+\mathrm{HS}^{-}(a q)\end{aligned}$
The auto - protolysis (self-ionisation) of water takes place. The reaction are as follows
$$\underset{\text { Acid }}{\mathrm{H}_2 \mathrm{O}(l)}+\underset{\text { Base }}{\mathrm{H}_2 \mathrm{O}}(l) \longrightarrow \underset{\begin{array}{c} \text { Conjugate } \\ \text { acid } \end{array}}{\mathrm{H}_3 \mathrm{O}^{+}}(a q)+\underset{\begin{array}{c} \text { Conjugate } \\ \text { base } \end{array}}{\mathrm{OH}^{-}(\mathrm{aq})}$$
Correlate the items listed in Column I with those listed in Column II. Find out as many correlations as you can.
| Column I | Column II | ||
|---|---|---|---|
| A. | Synthesis gas | 1. | $$\mathrm{Na_2[Na_4(PO_3)_6]}$$ |
| B. | Dihydrogen | 2. | Oxidising agent |
| C. | Heavy water | 3. | Softening of water |
| D. | Calgon | 4. | Reducing agent |
| E. | Hydrogen peroxide | 5. | Stoichiometric compounds of s-block elements |
| F. | Salt like hydrides | 6. | Prolonged electrolysis of water |
| 7. | Zn + NaOH | ||
| 8. | Zn + dil. H$$_2$$SO$$_4$$ | ||
| 9. | Synthesis of methanol | ||
| 10. | Mixture of CO and H$$_2$$ |
A. $\rightarrow(9,10)$
B. $\rightarrow(4,5,7,8,9)$
C. $\rightarrow(6)$
D. $\rightarrow(1,3)$
E. $\rightarrow(2,4)$
F. $\rightarrow(5)$
A. Synthesis gas - Synthesis of methanol
- Mixture of CO and H$$_2$$
$\begin{aligned} \text{B. Dihydrogen }\quad & - \text { Reducing agent } \\ & - \text { Stoichiometric compounds of } s \text {-block elements } \\ & -\mathrm{Zn}+\mathrm{NaOH} \\ & -\mathrm{Zn}+\text { dil. } \mathrm{H}_2 \mathrm{SO}_4 \\ & - \text { Synthesis of methanol }\end{aligned}$
C. Heavy water - Prolonged electrolysis of water
D. Calgon $-\mathrm{Na}_2\left[\mathrm{Na}_4\left(\mathrm{PO}_3\right)_6\right]$
- Softening of water
E. Hydrogen peroxide - Oxidising agent
— Reducing agent
F. Salt like hydrides - Stoichiometric compounds of s-block elements.
Match Column I with Column II for the given properties/applications mentioned therein.
| Column I | Column II | ||
|---|---|---|---|
| A. | H | 1. | used in the name of perhydrol. |
| B. | H$$_2$$ | 2. | can be reduced to dihydrogen by NaH. |
| C. | H$$_2$$O | 3. | can be used in hydroformylation of olefin. |
| D. | H$$_2$$O$$_2$$ | 4. | can be used in cutting and welding. |
A. $\rightarrow(4)$
B. $\rightarrow(3)$
C. $\rightarrow(2)$
D. $\rightarrow$ (1)
A. Atomic hydrogen $(\mathrm{H})$ can be used in cutting and welding.
B. Dihydrogen $\left(\mathrm{H}_2\right)$ can be used in hydroformylation of olefin.
C. Water $\left(\mathrm{H}_2 \mathrm{O}\right)$ can be reduced to dihydrogen by NaH .
D. Hydrogen peroxide $\left(\mathrm{H}_2 \mathrm{O}_2\right)$ used in the name of perhydrol.
Match the terms in Column I with the relevant item in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Electrolysis of water produces | 1. | atomic reactor |
| B. | Lithium aluminium hydride is used as | 2. | polar molecule |
| C. | Hydrogen chloride is a | 3. | recombines on metal surface to generate high temperature |
| D. | Heavy water is used in | 4. | reducing agent |
| E. | Atomic hydrogen | 5. | hydrogen and oxygen |
A. $\rightarrow(5)$
B. $\rightarrow$ (4)
C. $\rightarrow(2)$
D. $\rightarrow$ (1)
E. $\rightarrow$ (3)
A. Electrolysis of water produce hydrogen and oxygen.
B. Lithium aluminium hydride is used as reducing agent.
C. Hydrogen chloride is a polar molecule.
D. Heavy water is used in atomic reactor as moderator.
E. Atomic hydrogen recombines on metal surface to generate high temperature.
Match the items in Column I with the relevant item in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Hydrogen peroxide is used as a | 1. | zeolite |
| B. | Used in Calgon method | 2. | perohydrol |
| C. | Permanent hardness of hard water is removed by | 3. | sodium hexametaphosphate |
| 4. | propellant |
A. $\rightarrow(2,4)$
B. $\rightarrow$ (3)
C. $\rightarrow(1,3)$
A. Hydrogen peroxide is used as a perhydrol and propellant.
B. Sodium hexametaphosphate is used in Calgon method.
C. Permanent hardness of hard water is removed by zeolite and sodium hexametaphosphate.