The reaction between hydroxide ion, OH^-and phosphinate ions, \(\rm {H}_2 \mathrm{PO}_2^{-}\)

\(\mathrm{H}_2 \mathrm{PO}_2^{-}(\mathrm{aq})+\mathrm{OH}^{-}(\mathrm{aq}) \rightarrow \mathrm{H}_2(\mathrm{g})+\mathrm{HPO}_3^{2-}(\mathrm{aq})\)

has been studied by following the initial rate of formation of the gaseous product. The results are tabulated below :

S.N.

Initial concentration of \(\mathrm{H}_2 \mathrm{PO}_2^{-}(\mathrm{aq}) / \mathrm{mol}\ \mathrm{dm}^{-3}\)

Initial concentration of OH^- (aq)/mol dm^-3

Initial rate of H₂(g) evolution 10^-3 dm³ min^-1

1

0.6

1.0

2.3

2

0.6

2.0

9.5

3

0.1

6.0

14.4

4

0.2

6.0

28.7

What is the overall reaction order?

Question

S.N.	Initial concentration of \(\mathrm{H}_2 \mathrm{PO}_2^{-}(\mathrm{aq}) / \mathrm{mol}\ \mathrm{dm}^{-3}\)	Initial concentration of OH^- (aq)/mol dm^-3	Initial rate of H₂(g) evolution 10^-3 dm³ min^-1
1	0.6	1.0	2.3
2	0.6	2.0	9.5
3	0.1	6.0	14.4
4	0.2	6.0	28.7