Oxidation state of +1 for phosphorus is found in:
1. H3PO3
2. H3PO4
3. H3PO2
4. H4P2O7
Which of the following reactions does not represent a redox change?
1. CaCO3 →CaO + CO2
2. 2H2 + O2 →2H2O
3. Na + H2O → NaOH + 12H2
4. MnCl3 → MnCl2 + 12Cl2
If H2S is passed through an acidified K2Cr2O7 solution, the colour of the solution:
a. will remain unchanged
b. will change to deep red
c. will change to dark green
d. will change to dark brown
The oxidation number and covalency of sulphur in the sulphur molecule (S8) are respectively:
1. 0 and 2
2. +6 and 8
3. 0 and 8
4. +6 and 2
H2S is passed through an acidified solution of copper sulphate and a black precipitate is formed. This is due to:
1. oxidation of Cu2+
2. reduction of Cu2+
3. double decomposition
4. reduction and oxidation
The most common oxidation state of an element is -2. The number of electrons present in its outermost shell is:
1. 2
2. 4
3. 6
4. 8
4P + 3KOH + 3H2O → 3KH2PO2 + PH3:
Correct statement regarding the above reaction is -
1. P oxidised only
2. P is reduced only
3. P is oxidised as well as reduced
4. None of the above
In which SO2 acts as oxidant, while reacting with:
1. acidified KMnO4
2. acidified K2Cr2O7
3. H2S
4. H202
In the reaction;
3Br2 + 6CO2-3 + 3H2O →5Br- + BrO-3 + 6HCO-3
which statement is correct?
1. Br2 is oxidised
2. Br2 is reduced
3. Br2 is neither oxidised nor reduced
4. Br2 is oxidised and reduced as well
When NaCl is dissolved in water, the sodium ion becomes:
1. oxidised
2. reduced
3. hydrolysed
4. hydrated