Detergents are preferred over soaps in hard water because they:
A. Form soluble calcium and magnesium salts
B. Are natural
C. Are cheaper
D. Contain more carbon
Answer: Option A
Solution (By JKExamLibrary)
Detergents (e.g., sulfonates) do not precipitate with Ca²⁺/Mg²⁺, so they lather well in hard water. Soaps form insoluble scum. This is a major advantage.
Explanation:
Portland cement is made by heating a mixture of limestone (CaCO₃) and clay (SiO₂, Al₂O₃, Fe₂O₃) in a kiln. The resulting clinker is ground with gypsum. Soda ash and sand are for glass.
Explanation:
Broad-spectrum antibiotics are effective against a wide range of bacteria, including both Gram-positive and Gram-negative species. Chloramphenicol is a classic example of a broad-spectrum antibiotic. Penicillin is generally narrow-spectrum, primarily targeting Gram-positive bacteria.
Assertion (A): The smell of hot sizzling food reaches you several meters away, but to get the smell from cold food you have to go close. Reason (R): The kinetic energy of gas molecules is higher at higher temperatures.
A.A is true but R is false.
B.Both A and R are true but R is NOT the correct explanation of A.
C.Both A and R are true and R is the correct explanation of A.
Explanation:
At higher temperatures, the rate of diffusion increases because the kinetic energy of the gas molecules (food aroma) increases. Thus, the smell of hot food diffuses faster and reaches further. Both statements are correct, and the increased kinetic energy perfectly explains the enhanced diffusion rate observed in the assertion.
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