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

Give reasons for the following:

(i) Bond enthalpy of F₂ is lower than that of Cl₂.

(ii) PH₃ has lower boiling point than NH₃.

The complex ion `[Co(H_2O)_5 (ONO)]^(2+) `

(A) linkage isomer

(B) ionisation isomer

(C) co-ordination isomer

(D) geometrical isomer

Write the fomulae of the following compounds

Sodium hexanitrito- N - cobaltate (III)

Write the IUPAC name of the given compound:

When a coordination compound CoCl₃.6NH₃ is mixed with AgNO₃, 3moles of AgCl are precipitated per mole of the compound. Write the IUPAC name of the coordination compound.

For the complex [Fe(H₂O)₆]+3, write the hybridisation, magnetic character and spin of the complex. (At, number : Fe = 26)

Draw one of the geometrical isomers of the complex [Pt (en)₂Cl₂] ⁺² which is optically inactive

Define the following terms: Lyophilic colloid

Define the following terms: Associated colloids

Write a method by which lyophobic colloids can be coagulated.

Write the IUPAC name of the given compound:

Write down the IUPAC name of the following complex: [Co(NH₃)₅ (NO₂)](NO₃)₂

Using IUPAC norms, write the formula for the following: 

Potassium tetracyanidonickelate(II)

Give reasons for the following observations:

Physisorption decreases with increase in temperature.

Give reasons for the following observations: Addition of alum purifies the water

Give reasons for the following observations:

Brownian movement provides stability to the colloidal solution.

On the basis of crystal field theory, write the electronic configuration for d⁴ ion if Δ₀ > P.

What is the effect of temperature on chemisorption ?

Why is adsorption always exothermic?

Explain what is observed when an electric current is passed through a colloidal sol?