The density of the solution is 2.15 g mL^$$-$$1, then mass of 2.5 mL solution in correct significant figures is :

What fraction of Fe exists as Fe(III) in Fe_0.96O ?

(Consider Fe_0.96O to be made up of Fe(II) and Fe(III) only)

In one molal solution that contains 0.5 mole of a solute, there is

What mass of 95% pure CaCO₃ will be required to neutralise 50 mL of 0.5 M HCl solution according to the following reaction?

CaCO_3(s) + 2HCl_(aq) $$\to$$ CaCl_2(aq) + Co_2(g) + 2H₂O_(l)

[Calculate upto second place of decimal point]