(i) Consider the oxidation of nitric oxide to form `NO_(2)`
`2NO_((g))+O_(2(g)) to 2NO_(2(g))`
(a) Express the rate of the reaction in terms of changes in the concentration of NO, `O_(2) and NO_(2)`.
(b) At a particular instant, when `[O_(2)]` is decreasing at 0.2mol `L^(-1)s^(-1)` at what rate is `[NO_(2)]` increasing at that instant?
(ii) Classify the following as acid (or) base using Arrhenius concept
`1. HNO_(3)" " 2.Ba(OH)_(2)" "3. H_(3)PO_(4)" " 4. CH_(3)COOH`

Explanation

(i) (a) Rate `=(-1)/(2)(d[NO])/(dt)=(d[O_(2)])/(dt)=(1)/(2)(d[NO_(2)])/(dt)`
(b) `(-d[O_(2)])/(dt)=(1)/(2)(d[NO_(2)])/(dt)`
`(d[NO_(2)])/(dt)=2xx((-d[O_(2)])/(dt))=2xx0.2" mol "L^(-1)s^(-1)=0.4" mol "L^(-1)s^(-1)`
(ii) 1. `HNO_(3)` : Nitric acid, dissociates to give hydrogen ions in water.
`therefore HNO_(3)` is acid.
2. `Ba(OH)_(2)` : Barium hydroxide, dissociates to give hydroxyl ions in water.
`therefore Ba(OH)_(2)` is base.
3. `H_(3)PO_(4)` : Orthophosphoric acid, dissociates to give hydrogen ions in water.
`therefore H_(3)PO_(4) ` is acid.
4. `CH_(3)COOH` : Acetic acid, dissociates to give hydrogen ions in water.
`therefore CH_(3)COOH` is acid.