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

Account for the following:

CH₃CHO is more reactive than CH₃COCH₃ towards reaction with HCN.

Explain the following terms :

Half life period of a reaction (t_1/2)

 Following reaction takes place in the cell: 
`Zn(s) + Ag_2O(s)+H_2O(l) -> Zn^{2+}(aq) + 2Ag (s) + 2OH^- (aq)`
Calculate `Delta_r G^0` of the reaction

[Given ; `E^0_(Zn^{2+}//Zn)` = -0.76V

`E_((Zn^{2+}//Zn)) = 0.76V`

`E_(Ag^4//Ag)^0 = 0.80V, 1F = 96,500 C mol^-1 ]`
          

Define the following terms with a suitable example of each: 
 Bactericidal antibiotics 

 Out of    _{and  , which one is optically active and why ?}

Give one chemical test as an evidence to show that [Co (NH₃)₅Cl]  are ionisation isomers. 

The decomposition of a hydrocarbon has value of rate constant as 2.5×10⁴s^-1 At 27° what temperature would rate constant be 7.5×10⁴ × ³ s^-1if energy of activation is  19.147 × 10³ J mol^-1 ?

 Write a condition under which a bimolecular reaction is kinetically first order. Give an example of  such a reaction. (Given : log2 = 0.3010,log 3 = 0.4771, log5 = 0.6990).

 Predict the main product of the following reactions:

Why dextro and laevorotatory isomers of Butan-2-ol are difficult to separate by fractional distillation? 

Write a chemical reaction to show that the open structure of D-glucose contains the following :  

Five alcohol groups

Give reasons for the following:
The chemistry of actinoids elements is not so smooth as that of the lanthanoids.

Define the following term with a suitable example in each:
Broad-spectrum antibiotics

Define the following term with a suitable example in each:
Disinfectants

Why dextro and laevo rotatory isomers of Butan-2-ol are difficult to separate by fractional distillation?

At 100°C the vapour pressure of a solution containing 6.5 g a solute in 100 g water is 732 mm. If K_b = 0.52, the boiling point of this solution will be ______.

The coordination number of AB having rock salt geometry is ____________.

When a reversible work is done by a galvanic cell, the relationship between Gibbs free energy and emf of the cell is given by the relationship as ____________.

The chemical reaction in which reactants require high amount of activation energy are generally ____________.

The rate of chemical reaction becomes double for every 10° rise in temperature because of ____________.