Science (English Medium) Class 12 - CBSE Question Bank Solutions for Chemistry

 Following reactions occur at cathode during the electrolysis of aqueous copper(II) chloride solution :

On the basis of their standard reduction electrode potential (E°) values, which reaction is feasible at the cathode and why ?

An element X (molar mass = 60 g mol⁻¹) has a density of 6.23 g cm⁻³. Identify the type of cubic unit cell, if the edge length of the unit cell is 4 ✕ 10⁻⁸ cm.

Account for the following :

Reducing character decreases from SO2 to TeO₂.

Define an ideal solution and write one of its characteristics.

After the ban on plastic bags, students of a school decided to make people aware of the harmful effects of plastic bags on the environment and Yamuna River. To make the awareness more impactful, they organised a rally by partnering with other schools and distributed paper bags to vegetable vendors, shopkeepers and departmental stores. All the students pledged not to use polythene bags in the future to save the Yamuna River.

After reading the above passage, answer the following questions:
(i) What values are shown by the students?
(ii) What are bio-degradable polymers? Give one example.
(iii) Is polythene a condensation or an addition polymer?

Arrange the following in the order of the property indicated against set :
H₂O, H₂S, H₂Se, H₂Te − increasing acidic character.

Write the product formed on reaction of D-glucose with Br₂ water.

What type of intermolecular attractive interaction exists in the pair of methanol and acetone?

Define disinfectants with a Suitable example?

What are anionic detergents? Give an example ?

 Account for the following: 
On reaction with benzene sulphonyl chloride, primary amine yields product soluble in alkali whereas secondary amine yields product insoluble in alkali.

 What is the role of promoters and poisons in catalysis?

 Give reactions for the following: 
O – O single bond is weaker than S – S single bond. 

Define the following term with a suitable example: 
Cationic detergents

Write chemical equation in support of your answer. 
 Out of   Cl and  CH₂- Cl,  which one is more reactive towards nucleophilic substitution reaction and why? 

Write chemical equation in support of your answer. 
 Out of  Cl and O2N Cl. which one is more reactive  towards nucleophilic substitution reaction and why?

[NiCl₄]^2- is paramagnetic while [Ni(CO)₄] is  diamagnetic though both are tetrahedral. Why? (Atomic no. Ni = 28) 

Arrange the following in order of the property indicated set.
HF, HCl, HBr, HI - decreasing bond enthalpy.

What type of detergents are used in toothpaste?