NEET Sample Paper NEET Sample Test Paper-17

  • question_answer
    In an experiment, 4 g of\[{{M}_{2}}{{O}_{x}}\]oxide was reduced to 2.8 g of the metal. If the atomic mass of the metal is \[56\,g\,mo{{l}^{-1}},\] the number of 0 atoms in the oxide is

    A)  2                  

    B)       1                    

    C)       4                  

    D)       3                                

    Correct Answer: D

    Solution :

    \[{{M}_{2}}{{O}_{x}}\xrightarrow{\text{Reduction}}M\] Eq. of \[{{M}_{2}}{{O}_{x}}=Eq.\]of Metal \[\frac{\text{Weight}\,\text{of}\,{{\text{M}}_{\text{2}}}{{\text{O}}_{\text{x}}}}{\text{Equivalent}\,\text{weight}\,\text{of}\,{{\text{M}}_{\text{2}}}{{\text{O}}_{\text{x}}}}=\] \[\frac{\text{Weight}\,\text{of}\,\text{metal}}{\text{Equivalent}\,\text{weight}\,\text{of}\,\text{metal}}\,\text{=}\] \[\frac{4}{\frac{2\times 56+x\times 16}{2x}}=\frac{2.8}{\frac{56}{x}}\]                        (1) On solving we get, \[\frac{4}{56+8x}=\frac{2.8}{56}\] \[\frac{1}{14+2x}=\frac{1}{20}\] \[2x=6\] \[x=3.\] Hence, the oxide is\[{{M}_{2}}{{O}_{3}}.\] Hence, the correct option is (d).


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