A polystyrene, having formula Br₃C₆H₃(C₈H₈)_n was prepared by heating styrene with tribromobenzoyl peroxide in the abscense of air. If it was found to contain 10.46% bromine by weight. Find the value of n.

plz give complete solution.....

Let the weight of polystyrene prepared be 100 g

number of moles of Br in 100g of ploystyrene = 10.46 / 79.9 = 0.1309

From the formula of polystyrene , we have ,

number of moles of Br = 3 * number of moles of Br₃C₆H₃(C₈H₈)_n

0.1309 = 3 * Wt / molar weight

0.1309 = 3*100 / (314.7 + 44n)

0.1309 * ( 314.7 + 44n ) = 300

(314.7 + 44n) = 2291.825

44n = 2291.825 - 314.7

n = 1977.125/44

n = 44.93

n = 45 (approx)

Therefore value of n is 45

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