Balance the following equation by oxidation number method:
Zn + HNO₃ \(\rightarrow\)Zn(NO₃)₂ + NH₄NO₃ + H₂O

Balance the following equation by ion-electron method In acidic medium.
\(S_2O_3^{2-}+I_2\rightarrow S_2O_4^{2-}+SO_2+I^-\)

Balance the following equation by ion-electron method In acidic medium.
\(Cr{(OH)}_4^-+H_2O_2\rightarrow Cr{O}_4^{2-}\)

An insecticide has the following percentage composition by mass: 47.5% C, 2.54% H, and 50.0% Cl. Determine its empirical formula and molecular formulae. Molar mass of the substance is 354.5g mol^-1

The Mn³⁺ ion is unstable in solution and undergoes disproportionation to give Mn²⁺, MnO₂ and H⁺ ion. Write a balanced ionic equation for the reaction.

Calculate the percentage composition of the elements present in magnesium carbonate. How many kilogram of CO₂ can be obtained by heating 1 kg of 90 % pure magnesium carbonate.

\({ 2NH }_{ 3 }\left( g \right) +{ CO }_{ 2 }\left( g \right) \rightarrow \underset{Urea}{H_2N}-\overset { \underset { || }{ O } }{ C } -{ NH }_{ 2 }\left( aq \right) +{ H }_{ 2 }O(I)\)
In a process, 646 g of ammonia is allowed to react with 1.144 kg of CO₂ to form urea.
(i) If the entire quantity of all the reactants is not consumed in the reaction which is the limiting reagent ?
(ii) Calculate the quantity of urea formed and unreacted quantity of the excess reagent. The balanced equation is 
\(\overset { { 2NH }_{ 3 }+{ CO }_{ 2 } }{ \underset { { H }_{ 2 }NCON{ H }_{ 2 }+{ H }_{ 2 }O }{ \downarrow } } \)

Protons can be accelerated in particle accelerators. Calculate the wavelength (in Å) of such accelerated proton moving at 2.85 x 10⁸ ms^-1 (the mass of proton is 1.673 x 10^-27 Kg).

Calculate the uncertainty in the position of an electron, if the uncertainty in its velocity is 5.7 x 10⁵ ms^-1.

Explain the angular distribution function of 1s, 2s, 3s, 2p, 3d and 4f orbits.