Science (English Medium) Class 12 - CBSE Important Questions for Chemistry

 What is the role of promoters and poisons in catalysis?

 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. 

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

 Write the electronic configuration of Fe(III) on the basis of crystal field theory when it forms an octahedral complex in the presence of (i) strong field, and (ii) weak field ligand. (Atomic no.of Fe=26) 

Write IUPAC name of the complex [Pt(en)₂Cl₂]. Draw structures of geometrical isomers for this complex. 

Write structures of compounds A and B of the following reaction : 

Write structures of compounds A and B of the following reaction : 

A colloidal sol is prepared by the given method in the figure. What is the charge on hydrated ferric oxide colloidal particles formed in the test tube? How is the solution represented? 

How does chemisorption vary with temperature?

Answer the following question.
Write IUPAC name of the complex [Pt(en)₂CI₂]. Draw structures of geometrical isomers for this complex.

Write the hybridization and magnetic character of the following complexes:
[Fe(H₂O)₆]²⁺
(Atomic no. of Fe = 26)

Write the hybridization and magnetic character of the following complexes:
[Fe(CO)₅]
(Atomic no. of Fe = 26)

A colloidal sol is prepared by the given method in the figure. What is the charge on hydrated ferric oxide colloidal particles formed in the test tube? How is the sol represented?

How does chemisorption vary with temperature?

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

Why are low spin tetrahedral complexes not formed?

[Ni(H₂O)₆]²⁺ (aq) is green in colour whereas [Ni(H₂O)₄ (en)]²⁺ (aq)is blue in colour, give reason in support of your answer.

Write the formula and hybridization of the following compound:

tris(ethane-1, 2–diamine) cobalt(III) sulphate

In a coordination entity, the electronic configuration of the central metal ion is t_2g³ e_g¹

Is the coordination compound a high spin or low spin complex?