Polymers — Homi Bhabha Class 9 Chemistry MCQs with Solutions
Free Homi Bhabha Class 9 Chemistry Polymers MCQs with step-by-step solutions (8 questions). Part of Substances in Daily Use & Applied Chemistry. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Polymers · medium · theory
A polymer is a very large molecule made of many small repeating units called:
A. isotopes
B. ions
C. atoms only
D. monomers ✓ Correct
Solution: Polymers are formed by joining many small monomer units together.
Q2 — Polymers · medium · theory
Which of the following is a synthetic polymer?
A. Cotton
B. Nylon ✓ Correct
C. Wool
D. Silk
Solution: Nylon is a man-made (synthetic) polymer; cotton, silk and wool are natural.
Q3 — Polymers · hard · theory
Which of the following is a natural polymer?
A. Nylon
B. Polythene
C. Cellulose ✓ Correct
D. PVC
Solution: Cellulose (in plants) is a natural polymer; the others are synthetic.
Q4 — Polymers · medium · theory
A common plastic used to make bags and bottles is:
A. polythene ✓ Correct
B. bakelite only
C. rubber
D. nylon only
Solution: Polythene (polyethylene) is widely used for bags, bottles and packaging.
Q5 — Polymers · hard · theory
Plastics cause serious environmental problems mainly because they are:
A. easily burnt safely
B. natural
C. very expensive
D. non-biodegradable ✓ Correct
Solution: Most plastics are non-biodegradable, so they persist in the environment for a very long time.
Q6 — Polymers · easy · theory
A polymer such as polythene is best described as a
A. very large molecule built from many small repeating units joined together ✓ Correct
B. single tiny molecule that cannot be broken down any further
C. mixture of two different metals melted together
D. salt formed by the reaction of an acid with a base
Solution: A polymer is a giant molecule made by joining a very large number of small repeating units called monomers. Polythene, for instance, is formed by linking many ethene molecules together.
Q7 — Polymers · medium · theory
Bakelite is widely used to make electrical switches, plug tops and pan handles mainly because it is
A. a good conductor of both electricity and heat
B. a material that dissolves readily in warm water
C. a poor conductor of electricity and heat that does not soften on heating once set ✓ Correct
D. a soft metal that can easily be bent into any shape
Solution: Bakelite is a thermosetting plastic. It is a poor conductor (a good insulator) of electricity and heat and does not soften when heated after it has set, which makes it ideal for electrical fittings and handles.
Q8 — Polymers · hard · numerical
A sample of polythene has an average molar mass of 28000 g/mol. If it is built from ethene units of molar mass 28 g/mol, the average number of ethene units in one polythene molecule is about
A. 100
B. 28000
C. 1000 ✓ Correct
D. 280
Solution: Number of repeating units = molar mass of the polymer divided by the molar mass of one monomer = 28000 / 28 = 1000. So about 1000 ethene units join to form each polythene molecule.