Redox Reactions...

When $$SO_2$$ is passed through a solution of $$K_2Cr_2O_7$$ turns green. The change in oxidation state of chromium and sulphur are ___________________ respectively.

Amongst the following, identify the species with an atom in $$+6$$ oxidation state.

Number of moles of acidic $$KMnO_4$$ needed for complete oxidation of $$1$$ mole equimolar mixture of $$FeSO_4$$ and $$FeC_2O_4$$ is:

On passing $$CO_2$$ into aqueous yellow coloured $$CrO_4^{2-}$$ solution, an orange coloured $$Cr_2O_7^{2-}$$ solution is obtained. Is this oxidation or reduction? The reaction is given below:
$$CrO_4^{2-} (aq) \xrightarrow []{CO_2} Cr_2O_7^{2-}$$

The average oxidation states of sulphur in $$Na_2S_2O_3$$ and $$Na_2S_4O_6$$ are, respectively :

When $$KMnO_4$$ acts as an oxidising agent and ultimately forms $$MnO^{2-}_4$$,$$MnO_2$$, $$Mn_2O_3$$ and $$Mn^{2+}$$, then the number of electrons transferred per molecule of $$KMnO_4$$ in each case respectively, is:

When $$(NH_4)_2 Cr_2O_7$$ is heated $$Cr_2O_3$$ is produced as a produnct and some other by product are also produced. What is the type of reaction?

 How many substances have underlined atoms of different nature?
$$Na_2\underline{S_4}O_6,Na_2\underline{S_2}O_3,CaO\underline{Cl_2},\underline{N_2}H_4O_3,\underline{Fe_3}O_4,K\underline{I_3},Cr\underline{O_5},K_2\underline{Cr_2}O_7$$

Oxidation state of  'S' in sodium tetrathionate is :

Anhydride of an acid is formed by dehydration and oxidation number of central atom remains unchanged.
Acid : $$H_2N_2O_2, HNO_2, HNO_3$$
Anhydride : $$N_2O_5, N_2O, NO, N_2O_3$$
Correct match of acid with its anhydride is