Vinegar is a 4-8% solution of acetic acid (CH₃COOH) in water. Formic acid is in ant sting, citric in citrus fruits, lactic in curd. Acetic acid is used as preservative and condiment.
Assertion (A): A catalyst does not change the equilibrium yield of a reaction. Reason (R): A catalyst speeds up both the forward and backward reactions equally.
A.Both A and R are true and R is the correct explanation of A.
B.A is false but R is true.
C.A is true but R is false.
D.Both A and R are true but R is NOT the correct explanation of A.
Explanation:
A catalyst lowers the activation energy for both the forward and reverse reactions by the same amount. Therefore, it increases the rates of both reactions equally, allowing the system to reach equilibrium faster, but without changing the final equilibrium concentrations (yield). Both statements are correct and R explains A.
Explanation:
Tricalcium aluminate (C₃A) reacts quickly with water and is responsible for the flash setting of cement. Gypsum is added to control the rate of this initial set. Tricalcium silicate (C₃S) provides early strength. Dicalcium silicate (C₂S) gives later strength. Tetracalcium aluminoferrite (C₄AF) contributes to color and hardness. Cement composition is abbreviated in cement chemistry notation.
Explanation:
Graphite conducts electricity due to delocalized electrons in its structure and is chemically inert, allowing its use in electrodes for electrolysis and batteries. Diamond is an insulator. Hardness is not the reason; graphite is soft. It is opaque and black. Graphite electrodes are used in arc furnaces.
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