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Acidic oxide of period 3 means its either A, C, DX is the oxide of a Period 3 element. X reacts with water to give an acidic solution.

A solution is prepared by reacting 0.100g of X with excess water. This solution was neutralised

by exactly 25.0cm3

of 0.100moldm–3 sodium hydroxide solution.

What could be the identity of X?

A Al 2O3 B MgO C P4O10 D SO3

Need help with this

When so3 is dissolved in water it forms h2so4

H2so4 + 2naoh = na2so4 + 2h2o

note the mole ration of acid to base is 1: 2

Moles of naoh = concentration x volume

0.1 x 25/1000

= 2.5x10^-3

0.100g of x means that if its so3 then

mole = 0.100/16x3 +32

= 1.25x10^-3

which is exactly half

hence ans is D

hope it helps<3