Answer:
HBr > HCl > H2S > BH3
Step-by-step explanation:
In many acids, the magnitude of electronegativity of the nonmetal determines the strength of the acid. The less electronegative the non-metal is, the stronger the acidity of the acid.
This is because the less electronegative the nonmetal is, the more easily the H-X bond is broken since it is longer and weaker.
This explains the order of acid strength shown in the answer above.