MCQ
upsc-p1-science-tech-chemistry-applications MCQ - Practice Questions with Answers
Solve 8 upsc-p1-science-tech-chemistry-applications questions for RAS/RPSC preparation.
Practice questions
Q1With reference to materials chemistry, consider the following statements: 1. Thermoplastics soften on heating and can be reshaped. 2. Thermosetting plastics set irreversibly after curing. 3. Ceramics are generally hard and heat-resistant but can be brittle. Select the correct answer using the code given below.
All three statements are correct. Reheating can soften thermoplastics, whereas curing creates an irreversible thermoset structure. Ceramics commonly combine hardness and heat resistance with brittleness, so hardness should not be confused with toughness.
Q2Consider the following statements about ionic and covalent substances: 1. Ionic solids conduct electricity well in the solid state because their ions remain fixed in position. 2. Network covalent solids such as diamond and silicon dioxide can be very hard and have high melting points. Which of the statements given above is/are correct? Select the correct answer using the code given below.
Only statement 2 is correct. Ions fixed in an ionic solid cannot move freely, so the solid conducts poorly; conduction becomes possible when the substance is molten or dissolved. Extended covalent bonding makes diamond and silicon dioxide hard and high-melting.
Q3With reference to water chemistry, consider the following statements: 1. Temporary hardness caused by bicarbonates can be reduced by boiling. 2. Boiling removes dissolved heavy metals and salts from water. 3. Activated carbon can adsorb many organic molecules but does not remove every dissolved ion. Select the correct answer using the code given below.
Statements 1 and 3 are correct. Boiling can reduce bicarbonate-based temporary hardness and kill many pathogens, but it does not remove dissolved heavy metals or salts. Activated carbon adsorbs many organic molecules, not every dissolved ion.
Q4With reference to chemical reactions and electrochemistry, consider the following statements: 1. A catalyst provides an alternative reaction path with lower activation energy without being consumed in the net reaction. 2. Oxidation and reduction always occur together in a redox reaction. 3. Salt water slows the corrosion of iron by lowering electrical conductivity. Select the correct answer using the code given below.
Statements 1 and 2 are correct. A catalyst lowers the activation-energy barrier without net consumption, and oxidation and reduction are coupled in a redox reaction. Statement 3 is incorrect because salt water increases conductivity and therefore accelerates corrosion.
Q5Arrange the following water-treatment operations in the correct sequence: 1. Sedimentation 2. Disinfection 3. Coagulation 4. Filtration Select the correct answer using the code given below.
Coagulation first helps suspended matter form larger aggregates. Sedimentation then allows them to settle, filtration removes remaining particles, and disinfection controls pathogens. Therefore the sequence in option B is 3-1-4-2.
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More questions
6Arrange the following pH values in decreasing order of hydrogen-ion concentration: 1. pH 7.45 2. pH 5 3. pH 7.35 4. pH 6 Select the correct answer using the code given below.
7Match List I with List II and select the correct answer using the code given below: List I (Substance) 1. Sodium bicarbonate 2. Sodium hypochlorite 3. Activated carbon 4. Iodised salt List II (Use or chemical action) P. Mild antacid Q. Disinfecting bleach R. Adsorption of many organic molecules S. Prevention of iodine deficiency
8Match List I with List II and select the correct answer using the code given below: List I (Material) 1. Brass 2. Bronze 3. Stainless steel 4. Vulcanised rubber List II (Composition or structural feature) P. Copper and zinc Q. Copper and tin R. Chromium-based protective oxide layer S. Sulphur cross-links