X4O10
Let molar mass of X be y
molar mass =  4y + 10 x 16 = 4y+160
so, moles = 85.2 / (4y+160)
Moles of oxygen = 10 x [85.2 / (4y+160) ]
Mass of oxygen  = 16 x 10 x [85.2 / (4y+160) ]
which is 48.0
so, 48 = 16 x 10 x [85.2 / (4y+160) ]
Solve the equation to get y.
y = 31
        
             
        
        
        
Answer:    That is, the suffix of the compound is unchanged by the presence of the halogen, and the halogen is included as a prefix in the name. In acyl halides, the suffix -oyl chloride is appended to the name. For example, CH3CH2COCl is called propanoyl chloride.
Explanation:
 
        
             
        
        
        
It would be “To obey the law of conservation of mass”