Enzymes are biological catalysts. Which statement about them is correct?
A. They are highly specific in their action.
B. They work optimally at very high temperatures.
C. They are inorganic compounds.
D. They are consumed during the reaction.
Answer: Option A
Solution (By JKSSB Mock Tests)
Enzymes are proteins that act as catalysts, exhibiting high specificity for substrates (lock-and-key model). They are not consumed, denature at high temperatures, and are organic. Examples: amylase for starch, pepsin for proteins.
Explanation:
Calcium (Ca²⁺) and magnesium (Mg²⁺) ions react with soap anions to form insoluble precipitates (scum), preventing lather. Sodium and potassium soaps are soluble and lather well. So detergents are preferred in hard water because their calcium/magnesium salts are soluble. Hardness is measured in terms of CaCO₃ equivalent.
Explanation:
PVC is a good electrical insulator, resistant to chemicals and moisture, used for pipes, cable sheathing. Bakelite for switches; polystyrene for packaging.
Explanation:
Two or more substances combine to form a single product: N₂ + 3H₂ → 2NH₃. This is a combination (synthesis) reaction. Decomposition involves a single compound breaking down. Displacement: one element displaces another. Double displacement: exchange of ions. The Haber process for ammonia is also a redox and reversible reaction. Combination can be exothermic.
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