Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

Redox Reactions

Long Answer Type

121.

Write the various steps for balancing a redox equation by oxidation number method.

157 Views

Short Answer Type

122. Can you store copper sulphate solutions in a zinc pot?

135 Views

123.

Balance the following equation by oxidation number method.

$bold space bold space bold FeCl subscript bold 3 bold space bold plus bold space bold H subscript bold 2 bold S bold space bold space bold rightwards arrow bold space bold space bold space bold FeCl subscript bold 2 bold space bold plus bold space bold HCl bold space bold plus bold space bold S$

100 Views

124.
Balance the following equation by oxidation number method:
$straight P space plus space HNO subscript 3 space space rightwards arrow space space space HPO subscript 3 space plus space NO space plus space straight H subscript 2 straight O$

(i) The skeleton equation along with oxidation number of each atom is,

0 + 1 +5 -2 +1 +5 -2 +2 -2 +1 -2
P +H N O₃   H P O₃ N O +H₂ O

(ii) Noting the change in O.N. of above atoms,
Increase P = 0 to 5 i.e. 5
Decrease N = +5 to -2 i.e. 3

(iii) Equalise the increase/decrease in O.N. by multiplying P by 3 and HNO₃ by 5.
3P + 5HNO₃    HPO₃ + NO + H₂O

(iv) On counting and balancing the atoms on both sides, we get the balanced equation.
3P + 5HNO₃    3HPO₃ + 5NO + H₂O

104 Views

125.

Balance the following equation by oxidation number method:

$SnO subscript 2 space plus space straight C space rightwards arrow space space space Sn space plus space CO$

100 Views

126. Balance the equation by oxidation number method:

bold space bold Fe subscript bold 2 bold O subscript bold 3 bold space bold plus bold space bold C bold space bold space bold rightwards arrow bold space bold space bold space bold space bold Fe bold space bold plus bold space bold CO

106 Views

Long Answer Type

127. Balance the euqation by oxidation number method:

straight C subscript 6 straight H subscript 6 space plus space straight O subscript 2 space space space rightwards arrow space space space CO subscript 2 space plus space space straight H subscript 2 straight O

196 Views

128. Balance the following,chemical equation by oxidation number method:

FeS subscript 2 space plus space straight O subscript 2 space space rightwards arrow space space space Fe subscript 2 straight O subscript 3 space plus space SO subscript 2

148 Views

129. Balance the following,chemical equation by oxidation number method:

Mn to the power of 2 plus end exponent space plus space straight S subscript 2 straight O subscript 8 superscript 2 minus end superscript space space space space rightwards arrow space space space space stack MnO subscript 4 superscript minus space plus space HSO subscript 4 superscript minus with left parenthesis acidic space medium right parenthesis below

148 Views

130.

Balance the following chemical equation by oxidation number method:
$Zn space plus space NO subscript 3 superscript minus space space rightwards arrow space space space Zn to the power of 2 plus end exponent space plus space left parenthesis NH subscript 4 right parenthesis to the power of plus$ in acidic medium.