The pH of the soil is tested, and for the better growth of crops, slightly alkaline soil is required. Which ion in the fertiliser will increase the alkalinity of the soil?

1. Hydronium ion
2. Hydroxyl ion
3. Hydrogen ion
4. Both hydroxyl and hydrogen

Ramu makes a detailed study on the values of electronegativity and the formation of compounds. Accordingly, he draws the following conclusion:

The larger the electronegativity (EN) difference between the combining atoms, the more ionic bonds will form.

If the EN difference is negligible, covalent bonds will form. So, which of the following values refers to covalent bonds?

P: 3.0 and 3.0
Q: 0.9 and 3.0

1. Only P
2. Only Q
3. Both P and Q
4. Neither P nor Q

The diagram shown is a wrong attempt to electroplate a pan with copper:

Which of the following could have been done to copper plate a pan?

1. To change DC to AC.
2. To change the electrolyte from copper sulphate to cobalt sulphate.
3. Connect the pan to the negative electrode.
4. To induce a higher current.

During the extraction of aluminium by Hall Heroult’s process, the carbon rods are replaced continuously. This is because:

1. It minimises heat loss by radiation.
2. It enhances the mobility of ions.
3. The carbon anode is consumed.
4. It lowers the fusion point.