PART - 2 CH - 7 Redox Reactions — Chemistry STD 11 Science — Question

Equal volumes of 0.002M solutions of sodium iodate and cupric chlorate are mixed together. Will it lead to precipitation of copper iodate? (For cupric iodate K_sp = 7.4 × 10^–8 ).

Perform the following calculations and express the results to proper number of significant figures.

1. 144.3 m² + (2.54 m × 8.4 m).
2. (4.05 × 10²mL) - (0.0225 × 10²mL).
3. (3.50 × 10²cm) (4.00 × 10⁶cm).

Calculate the pH of a buffer which is 0.1M in acetic acid and 0.15M in sodium acetate. Given that the ionisation constants of acetic acid is 1.75 × 10^-5. Also calculate the change in pH of the buffer if to 1L of the buffer (i) 1cc of 1M NaOH are added. (ii) 1cc of 1M HCl are added. Assume that the charge in volume is negligible. (iii) What will be the buffer index of the above buffer?

What are the necessary conditions for any system to be aromatic?

The ionization constant of dimethylamine is 5.4 × 10^–4. Calculate its degree of ionization in its 0.02M solution. What percentage of dimethylamine is ionized if the solution is also 0.1M in NaOH?

Three students, Manish, Ramesh and Rajni were determining the extra elements present in an organic compound given by their teacher. They prepared the Lassaigne’s extract (L.E.) independently by the fusion of the compound with sodium metal. Then they added solid FeSO₄ and dilute sulphuric acid to a part of Lassaigne’s extract. Manish and Rajni obtained prussian blue colour but Ramesh got red colour. Ramesh repeated the test with the same Lassaigne’s extract, but again got red colour only. They were surprised and went to their teacher and told him about their observation. Teacher asked them to think over the reason for this. Can you help them by giving the reason for this observation. Also, write the chemical equations to explain the formation of compounds of different colours.

Define the first law of thermodynamics and also derive its mathematical form.

The work function for caesium atom is 1.9eV. Calculate,

1. The threshold wavelength.
2. The threshold frequency of the radiation.

If the caesium element is irradiated with a wavelength 500nm, calculate the kinetic energy and the velocity of the ejected photoelectron.

The work function for caesium atom is 1.9 eV . Calculate (a) the threshold wavelength and (b) the threshold frequency of the radiation. If the caesium element is irradiated with a wavelength 500 nm , calculate the kinetic energy and the velocity of the rejected photoelectron.