List of top Questions asked in CBSE Class XI

The ionization constant of chloroacetic acid is 1.35 × 10^–3. What will be the pH of 0.1M acid and its 0.1M sodium salt solution?

Write the formulae for the following compounds: 
(a) Mercury (II) chloride (b) Nickel (II) sulphate 
(c) Tin (IV) oxide (d) Thallium (I) sulphate 
(e) Iron (III) sulphate (f) Chromium (III) oxide

Suggest a list of the substances where carbon can exhibit oxidation states from -4 to +4 and nitrogen from -3 to +5.

While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why?

Depict the galvanic cell in which the reaction Zn(s) + 2Ag⁺ (aq) \(\rightarrow\)  Zn²⁺ (aq) + 2Ag(s) takes place, further show: 

1. which of the electrode is negatively charged, 
2. the carriers of the current in the cell, and
3. individual reaction at each electrode.

Given the standard electrode potentials,
K⁺ /K = -2.93V,
Ag⁺/Ag = 0.80V, 
Hg²⁺/Hg = 0.79V 
Mg²⁺/Mg = -2.37V.
Cr³⁺/Cr = -0.74V
Arrange these metals in their increasing order of reducing power.

Calculate the wavelength, frequency and wave number of a light wave whose period is \(2.0×10^{–10}\ s\).

The ionic product of water at 310 K is 2.7 × 10^–14. What is the pH of neutral water at this temperature?

Calculate the pH of the resultant mixtures: 
a) 10 mL of 0.2M Ca(OH)₂ + 25 mL of 0.1M HCl 
b) 10 mL of 0.01M H₂SO₄ + 10 mL of 0.01M Ca(OH)₂
c) 10 mL of 0.1M H₂SO₄ + 10 mL of 0.1M KOH

Arrange the following metals in the order in which they displace each other from the solution of their salts.
Al, Cu, Fe, Mg and Zn.

What is the number of photons of light with a wavelength of 4000 pm that provide 1J of energy?

Predict the products of electrolysis in each of the following:

1. An aqueous solution of \(AgNO_3\) with silver electrodes
2. An aqueous solution \(AgNO_3\) with platinum electrodes 
3. A dilute solution of \(H_2SO_4\) with platinum electrodes 
4. An aqueous solution of \(CuCl_2\) with platinum electrodes.

Refer to the periodic table given in your book and now answer the following questions:

1. Select the possible non metals that can show disproportionation reaction. 
2. Select three metals that can show disproportionation reaction

Consider the elements: \(Cs\), \(Ne\), \(I\) and \(F\)

1. Identify the element that exhibits only negative oxidation state. 
2. Identify the element that exhibits only postive oxidation state. 
3. Identify the element that exhibits both positive and negative oxidation states.
4. Identify the element which exhibits neither the negative nor does the positive oxidation state.

Determine the solubilities of silver chromate, barium chromate, ferric hydroxide, lead chloride and mercurous iodide at 298K from their solubility product constants.Determine also the molarities of individual ions.

to be wound up

to meet one’s match

Briefly comment on "The purpose of the author’s journey to Mount Kailash."

Distinguish between the following pairs of sentences.
(i) He was visibly moved.
(ii) He was visually impaired.

Distinguish between the following pairs of sentences.
(i) Green and black stripes were used alternately.
(ii) Green stripes could be used or alternatively black ones.

Briefly comment on “As a Buddhist, he told me, he knew that it didn’t really matter if I passed away, but he thought it would be bad for business.”

What do the following utterances indicate?
(i) “I told her, through Daniel …”
(ii) “It’s a cold,” he said finally through Tsetan

Guess the meaning of the following words.
kora, drokba, kyang
In which language are these words found?

Briefly comment on "Tsetan’s support to the author during the journey."

Briefly comment on "The author’s meeting with Norbu."