volumetric analysis

[recovered]

hi guys just neeed help wiht these questions

it says
calcium hydrochlorite,Ca(OCL)2 when placed in water reacts with hydronium ions to form hypochlorous acid(HOCL)
THEN THE equation states OCL^-(aq) + H30^+(aq) forms HOCL(aq) + H2O(l)
A 20.0g sample of calcium hydrochlorite was dissolved in water in a 250ml volumetric flask. A 25.00 ml aliquot was pipetted into a falsk and excess acidified iodide ions,I^- were added. The hypochlorite ions produced chloride ions , CL^-, while the iodide , liberated iodine, I2

a)i) write the reduction half equation
ii) oxidation half equation
iii)overall equation

when titrated, the following titres of 1.020 M of KI(aq) were used 19.05ml, 19.25ml, 17.85ml and 18.95ml
b)i) calculate the number of moles
ii) number of moles of OCL^- in the 25ml aliquot
iii) number of moles of OCL^0 in the 250ml flask
iv) calculate % mass of Ca(OCl)2

thnks guys