Class 12 Chemistry - Chapter Surface Chemistry NCERT Solutions | Give four examples of heterogeneous cata

Explain what is observed

(i) When a beam of light is passed through a colloidal sol.

(ii) An electrolyte, NaCl is added to hydrated ferric oxide sol.

(iii) Electric current is passed through a colloidal sol?

Why is adsorption always exothermic?

What do you mean by activity and selectivity of catalysts?

What modification can you suggest in the Hardy-Schulze law?

Explain the following terms:

(i) Electrophoresis

(ii) Coagulation

(iii) Dialysis

(iv) Tyndall effect.

What is an adsorption isotherm? Describe Freundlich adsorption isotherm.

Explain the terms with suitable examples:

(i) Alcosol

(ii) Aerosol

(iii) Hydrosol

How are colloids classified on the basis of

(i) Physical states of components

(ii) Nature of dispersion medium and

(iii) Interaction between dispersed phase and dispersion medium?

Discuss the effect of pressure and temperature on the adsorption of gases on solids.

Why does physisorption decrease with the increase of temperature

For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.

Write the formulas for the following coordination compounds:

(i) Tetraamminediaquacobalt (III) chloride

(ii) Potassium tetracyanonickelate(II)

(iii) Tris(ethane-1,2-diamine) chromium(III) chloride

(iv) Amminebromidochloridonitrito-N-platinate(II)

(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate

(vi) Iron(III) hexacyanoferrate(II)

(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N

(ii) Write IUPAC names of all the isomers.

(iii) What type of isomerism is exhibited by different pairs of amines?

Why are solids rigid?

Write the structures of the following compounds.

(i) α-Methoxypropionaldehyde

(ii) 3-Hydroxybutanal

(iii) 2-Hydroxycyclopentane carbaldehyde

(iv) 4-Oxopentanal

(v) Di-sec-butyl ketone

(vi) 4-Fluoroacetophenone

Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?

Why are pentahalides more covalent than trihalides?

Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?

Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.

Write structures of the following compounds:

(i) 2-Chloro-3-methylpentane

(ii) 1-Chloro-4-ethylcyclohexane

(iii) 4-tert. Butyl-3-iodoheptane

(iv) 1,4-Dibromobut-2-ene

(v) 1-Bromo-4-sec. butyl-2-methylbenzene

How do you explain the absence of aldehyde group in the pentaacetate of D-glucose?

What are essential and non-essential amino acids? Give two examples ofeach type.

What is the covalence of nitrogen in N₂O₅?

Boiling point of water at 750 mm Hg is 99.63°C. How much sucrose is to be added to 500 g of water such that it boils at 100°C.Molal elevation constant for water is 0.52 K kg mol^-1.

Write the equation of the reaction of hydrogen iodide with:

(i) 1-propoxypropane

(ii) Methoxybenzene and

(iii) Benzyl ethyl ether

A solution of Ni(NO₃)₂ is electrolysed between platinum electrodes using a current of 5 amperes for 20 minutes. What mass of Ni is deposited at the cathode?

If the density of some lake water is 1.25 g mL^-1 and contains 92 g of Na⁺ ions per kg of water, calculate the molality of Na⁺ ions in the lake.

State Henry's law and mention some important applications?

Distinguish between the terms homopolymer and copolymer and give an example of each.

Explain:   (i) Zone refining    (ii) Column chromatography.