An indicator that remains colorless in acid and turns pink in base is:
A. Turmeric
B. Litmus
C. Phenolphthalein
D. Methyl orange
Answer: Option C
Solution (By JKExamLibrary)
Phenolphthalein: pH range 8.3–10; colorless below 8.3, pink above. Litmus is red in acid, blue in base. Methyl orange red in acid, yellow in base. Turmeric yellow in acid, reddish-brown in base.
Explanation:
Calorific value is the heat produced by combustion of unit mass, expressed in energy per mass: kJ/kg, J/g, kcal/kg. Higher CV means better fuel. Determined by bomb calorimeter.
Explanation:
Hydrogen peroxide is a strong oxidizing agent. In dilute solutions (3-6%), it is used as a mild antiseptic for minor cuts and as a bleaching agent for hair, teeth, and delicate materials like silk and wool. It decomposes into water and oxygen.
Explanation:
H₂O₂ releases oxygen that kills bacteria (antiseptic) and bleaches colored materials. Ethanol is disinfectant but not strong bleach. Methanol is toxic.
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