PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions

Account for the following : Nitrogen does not form pentahalide.

Write the structure of 2-methylbutanal.

Why are solids rigid?

Why do solids have a definite volume?

Classify the following as amorphous or crystalline solids:

Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

Why is glass considered a super cooled liquid?

Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show cleavage property?

Define the term ‘amorphous’.

What makes a glass different from a solid such as quartz? Under what conditions could quartz be converted into glass?

‘Stability of a crystal is reflected in the magnitude of its melting points.’ Comment. Collect melting points of solid water, ethyl alcohol, diethyl ether and methane from a data book. What can you say about the intermolecular forces between these molecules?

Can you store copper sulphate solutions in a zinc pot?

Arrange the following metals in the order in which they displace each other from the solution of their salts.

\[\ce{Al, Cu, Fe, Mg}\] and \[\ce{Zn}\]

Explain the bonding in coordination compounds in terms of Werner’s postulates.

FeSO₄ solution mixed with (NH₄)₂SO₄ solution in 1 : 1 molar ratio gives the test of Fe²⁺ ion but CuSO₄ solution mixed with aqueous ammonia in 1 : 4 molar ratio does not give the test of Cu²⁺ ion. Explain why?

How many ions are produced from the complex Co(NH₃)₆Cl₂ in solution?

How are polymers classified on the basis of structure?

What is natural polymer? Give two examples of natural polymers.

Name the macromolecules that are chosen as drug targets.

Which forces are involved in holding the drugs to the active site of enzymes?

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