How is phosphoric acid prepared industrially?

Give equations to show how the following is made from its corresponding anhydride.

Sulphuric acid.

Give a balanced equation for the method of preparation of acid:

By reaction between an acidic gas and a neutral liquid.

Explain the following:

Nitrogen dioxide is a double acid anhydride.

Give equations to show how the following is made from its corresponding anhydride.

sulphurous acid.

Give a balanced equation for the method of preparation of acid:

By reaction between non-volatile acid and a salt.

Give equations to show how the following is made from its corresponding anhydride.

Phosphoric acid.

Identify the acid formed in the given reaction:

${\mathrm{H}}_2{\mathrm{SO}}_4+\mathrm{NaCl} \stackrel{\mathrm{high} \mathrm{temperature}}{\to } {\mathrm{NaHSO}}_4 + \mathrm{\_\_\_\_\_}$

Give equations to show how the following is made from its corresponding anhydride.

Carbonic acid.

Give a balanced equation for the method of preparation of acid:

By reaction between volatile acid and a non-metal.

Choose an oxide which when dissolved in water form acid from $\left[{\mathrm{SO}}_2, {\mathrm{SiO}}_2, {\mathrm{Al}}_2{\mathrm{O}}_3, \mathrm{CO}, \mathrm{MgO}, {\mathrm{Na}}_2\mathrm{O}\right]$.