KVPY Sample Paper KVPY Stream-SX Model Paper-9

  • question_answer
    \[{{H}_{2}}{{O}_{2}}+2KI\xrightarrow{40%yield}{{I}_{2}}+2KOH\]
    \[{{H}_{2}}{{O}_{2}}+2KMn{{O}_{4}}+3{{H}_{2}}S{{O}_{4}}\xrightarrow{50%yield}\]\[{{K}_{2}}S{{O}_{4}}+2MnS{{O}_{4}}+3{{O}_{2}}+4{{H}_{2}}O\]
    150 mL of \[{{H}_{2}}{{O}_{2}}\] sample was divided into two parts. First part was treated with KI and formed KOH required 200 mL of M/2 \[{{H}_{2}}S{{O}_{4}}\] for neutralization. Other part was treated with \[KMn{{O}_{4}}\] yielding 6.74 litre of \[{{O}_{2}}\] at STP. Using % yield indicated find volume strength of \[{{H}_{2}}{{O}_{2}}\]sample used.
    \[{{H}_{2}}{{O}_{2}}+2KI\xrightarrow{40%yield}{{I}_{2}}+2KOH\]
    \[{{H}_{2}}{{O}_{2}}+2KMn{{O}_{4}}+3{{H}_{2}}S{{O}_{4}}\xrightarrow{50%yield}\]\[{{K}_{2}}S{{O}_{4}}+2MnS{{O}_{4}}+3{{O}_{2}}+4{{H}_{2}}O\]

    A) 5.04                             

    B) 10.08

    C) 3.36     

    D) 33.6

    Correct Answer: D

    Solution :

    Mole of \[{{H}_{2}}S{{O}_{4}}=0.1,\] mole of KOH = 0.2 Mole of \[{{H}_{2}}S{{O}_{4}}\] used in first reaction  \[=\frac{0.2}{2}\,\,\times \,\,\frac{1}{0.4}=0.25\]
    Mole of produced \[{{O}_{2}}=\frac{6.74}{22.4}=0.3\]
    Mole of used in second reaction  \[=\frac{0.3}{3\,\,\times \,\,0.5}=0.2\]
    Total mole of consumed \[{{H}_{2}}{{O}_{2}}=0.45\]
    Molarity of \[{{H}_{2}}{{O}_{2}}=\frac{0.45}{0.15}=3M\]
    Volume strength \[112\,\,\times \,\,3=33.6\]


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