An electrochemical cell that converts chemical energy into electrical energy is called:
A. Electrolytic cell
B. Both B and C
C. Daniel cell
D. Galvanic cell
Answer: Option B
Solution (By JKSSB Mock Tests)
A galvanic (or voltaic) cell generates electrical energy from a spontaneous chemical reaction. The Daniel cell is a specific, classic type of galvanic cell using zinc and copper electrodes. An electrolytic cell does the reverse, using electrical energy to drive a non-spontaneous chemical reaction.
Explanation:
Fermentation is an anaerobic biological process in which enzymes (zymase) convert glucose to ethanol and CO₂: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂. Oxidation would require oxygen. Esterification forms esters, saponification makes soap. Fermentation is used in brewing, winemaking, and baking (where CO₂ makes bread rise). The temperature is kept around 30-35°C.
Explanation:
Hydration of cement is exothermic (heat of hydration). In large concrete pours, this heat can cause thermal cracking. Cooling is sometimes needed.
Explanation:
Baking powder contains sodium bicarbonate (NaHCO₃) and a weak solid acid such as tartaric acid or cream of tartar (potassium hydrogen tartrate). When moistened, they react to produce CO₂, making dough rise. Baking soda alone requires an acidic ingredient (yogurt, lemon). The acid in baking powder ensures reliable leavening. Sodium chloride and calcium carbonate do not serve this purpose.
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