To determine the number of white coloured salts among the listed compounds, we look at their common color characteristics:

(a) $\mathrm{SrSO}_4$ - Generally, most sulfate salts are white unless the cation imparts a color. Strontium sulfate is indeed white.

(b) $\mathrm{Mg}\left(\mathrm{NH}_4\right)\mathrm{PO}_4$ - Magnesium ammonium phosphate is also known to be white. This is typical for many phosphates with colorless cations.

(c) $\mathrm{BaCrO}_4$ - Barium chromate is well-known for its yellow color, a characteristic of many chromates.

(d) $\mathrm{Mn}(\mathrm{OH})_2$ - Manganese hydroxide can have a faint pink to white color, but in this context, we consider it white for counting purposes.

(e) $\mathrm{PbSO}_4$ - Lead sulfate is white, consistent with many lead salts not influenced by strong coloring anions.

(f) $\mathrm{PbCrO}_4$ - Lead chromate is distinguished by its yellow color, again a feature of chromate salts.

(g) $\mathrm{AgBr}$ - Silver bromide is known for its pale yellow to virtually white appearance, but it is more accurately described as pale yellow.

(h) $\mathrm{PbI}_2$ - Lead iodide exhibits a bright yellow color, typical for many iodides with heavy metal cations.

(i) $\mathrm{CaC}_2\mathrm{O}_4$ - Calcium oxalate is white, as most insoluble oxalates are.

(j) $\left[\mathrm{Fe}(\mathrm{OH})_2\left(\mathrm{CH}_3\mathrm{COO}\right)\right]$ - This complex containing iron is brown red due to the presence of iron ions.

Summarizing, the white salts among the given compounds are $\mathrm{SrSO}_4$, $\mathrm{Mg}\left(\mathrm{NH}_4\right)\mathrm{PO}_4$, $\mathrm{Mn}(\mathrm{OH})_2$, $\mathrm{PbSO}_4$, and $\mathrm{CaC}_2\mathrm{O}_4$, making a total of 5 white colored salts.