2.2g of a compound of phosphorous and sulphur has 1.24g of P in it.Determineits empirical formula.

							









    

        

            

            
Elements
            
            

            
Given mass
            
            

            
%
            
            

            
Atomic mass
            
            

            
Moles
            
            

            
Mole ratio
            
            

            
Whole no. ratio
            
        
        

            

            
P
            
            

            
1.24g
            
            

            
56.4
            
            

            
30.974
            
            

            
1.8
            
            

            
1.3
            
            

            
13
            
        
        

            

            
S
            
            

            
0.96
            
            

            
43.6
            
            

            
32.065
            
            

            
1.4
            
            

            
1
            
            

            
10
            
        
    


So the empirical formula is P13S10
						

							
atomic weight of P : 31  and S :32
wt of P:1.24g and wt pf  : 0.96g
ratio of moles of P:S = (1.24/31) : (0.96/32) 
                                     = 4:3
empirical formula is : nP4S3
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							Ratio of P and the compound is 1.24 to 2,2 is 0.564In compound P4S3 , mass of P is 124g  and total mass of P4S3 is 220.  Ratio is 124/220 =0.564So, answer is option3, P4S3.