Science (English Medium) कक्षा ११ - CBSE Question Bank Solutions

Match the following species with their corresponding ground state electronic configuration.

Match the quantum numbers with the information provided by these.

Match the following

Match species given in Column I with the electronic configuration given in Column II.

Which of the following property of water can be used to explain the spherical shape of rain droplets?

How does the surface tension of a liquid vary with increase in temperature?

The magnitude of surface tension of liquid depends on the attractive forces between the molecules. Arrange the following in increasing order of surface tension:

water, alcohol \[\ce{(C2H5OH)}\] and hexane \[\ce{[CH3(CH2)4CH3)]}\].

Name two phenomena that can be explained on the basis of surface tension.

Why does sharp glass edge become smooth on heating it upto its melting point in a flame? Explain which property of liquids is responsible for this phenomenon.

Explain the term ‘laminar flow’. Is the velocity of molecules same in all the layers in laminar flow? Explain your answer.

The fragrance of flowers is due to the presence of some steam volatile organic compounds called essential oils. These are generally insoluble in water at room temperature but are miscible with water vapour in vapour phase. A suitable method for the extraction of these oils from the flowers is ______.

If a liquid compound decomposes at its boiling point, which method (s) can you choose for its purification. It is known that the compound is stable at low pressure, steam volatile and insoluble in water.

By mistake, an alcohol (boiling point 97°C) was mixed with a hydrocarbon (boiling point 68°C). Suggest a suitable method to separate the two compounds. Explain the reason for your choice.

Assertion (A): Components of a mixture of red and blue inks can be separated by distributing the components between stationary and mobile phases in paper chromatography.

Reason (R): The coloured components of inks migrate at different rates because paper selectively retains different components according to the difference in their partition between the two phases.

You have a mixture of three liquids A, B and C. There is a large difference in the boiling points of A and rest of the two liquids i.e., B and C. Boiling point of liquids B and C are quite close. Liquid A boils at a higher temperature than B and C and boiling point of B is lower than C. How will you separate the components of the mixture. Draw a diagram showing set up of the apparatus for the process.

A liquid with high boiling point decomposes on simple distillation but it can be steam distilled for its purification. Explain how is it possible?

Despite their - I effect, halogens are o- and p-directing in haloarenes. Explain.

Suggest a route to prepare ethyl hydrogensulphate (CH₃ – CH₂ – OSO₂ – OH) starting from ethanol (C₂H₅OH).

An alkene ‘A’ contains three C – C, eight C – H σ bonds and one C – C π bond. ‘A’ on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write IUPAC name of ‘A’.

Calcium carbonate reacts with aqueous HCl to give CaCl₂ and CO₂ according to the reaction,

\[\ce{CaCO_{3(s)} + 2 HCl_{(aq)} → CaCl_{2(aq)} + CO_{2(g)} + H2O_{(l)}}\]

What mass of CaCO₃ is required to react completely with 25 mL of 0.75 M HCl?