PART - 2 CH - 9 Hydrocarbons — Chemistry STD 11 Science — Question

Chlorine is prepared in the laboratory by treating manganese dioxide (MnO₂) with aqueous hydrochloric acid according to the reaction
4HCl_(aq) + MnO_2(s) → 2H₂O_(l) + MnCl_2(aq) + Cl_2(g)
How many grams of HCl react with 5.0g of manganese dioxide?

Lifetimes of the molecules in the excited states are often measured by using pulsed radiation source of duration nearly in the nano second range. If the radiation source has the duration of 2 ns and the number of photons emitted during the pulse source is 2.5 × 10¹⁵, calculate the energy of the source.

The pH of 0.005M codeine (C₁₈H₂₁NO₃) solution is 9.95. Calculate its ionization constant and pK_b.

Describe the linear combination of atomic orbitals in the formation of molecular orbitals.

Explain why cation are smaller and anions larger in radii than their parent atoms?

The buffers of X and Y of pH 4.0 and 6.0 respectively are prepared from acid HA and the salt Na A.
Both the buffers are 0.50M in HA. What would be the pH of the solution obtained by mixing equal volumes of the two buffers?
(K_HA = 1.0 × 10^-5)

Graphically show the total work done in an expansion when the state of an ideal gas is changed reversibly and isothermally from (p_i, V_i ) to (p_f, V_f ). With the help of a pV plot compare the work done in the above case with that carried out against a constant external pressure p_f.

Explain the oxidation number method to balance the redox reaction with explain.

An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol.