Question

An element, X forms an oxide in which mass % of oxygen is 48%. The formula of the oxide is (atomic weight of X = 52) Choose one: X2O XO3 XO X2O4

Answer 1

Here oxide = 48%
And element X will be 100 - 48 = 52%

so

48/16=3 and 52/52 =1

so formula of oxide = XO3

Answer 2

we can directly check the options or there is one more method that is
given that the mass percent of oxygen is 48% then
ab dimmag is taraf le jaao ki oxygen ka mass Hai 48% and given is that X has a weight of 52 so
hum dekh sakte Hain ki 48 + 52 is 100 toh yahin par click karna chahiye ki oxygen ke agar main 3 parts let Hoon and X ka sirf ek toh kaam ban jaayeya therefore the answer is XO3 which satisfies all our requirements for the question
thank u