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Class 9Class 10First YearSecond Year
$21. In electroplating of silver from where \mathrm{Ag}^{+} ions come and where they deposit?$  now playing

$21. In electroplating of silver from where \mathrm{Ag}^{+} ions come and where they deposit?$  $2. Which one is Alloy.(a) Graphite(b) Mercury(c) Steel(d) Water$  $(c) Calculate the oxidation number of chromium in the following compounds.(i) \mathrm{CrCl}_{3}$  $4. What is Alloy? Explain its classification with examples.$  $9. \mathrm{lg} equivalent weight of \mathrm{Al} is equal to(a) 9 \mathrm{~g} (b) 27 \mathrm{~g} (c) 54 \mathrm{~g} (d) \mathrm{lg}$  $Q.15 Will the reaction be spontaneous for the following set of half reactions.What will be the value of E_{\text {cell }} ?(i) \mathrm{Cr}^{3+}{ }_{(\mathrm{aq})}+3 \mathrm{e}^{-} \rightarrow \mathrm{Cr}_{(\mathrm{s})} (ii) \mathrm{MnO}_{2(3)}+4 \mathrm{H}^{+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Mn}^{2+}{ }_{\text {(a) })}+2 \mathrm{H}_{2} \mathrm{O}_{(0)} (Standard reduction potential for reaction(i) =-0.74 \mathrm{~V} and for the reaction (ii) =+1.28 \mathrm{~V} ).$  