The metal used in the manufacture of stainless steel is:
A. Copper
B. Zinc
C. Chromium
D. Lead
Answer: Option C
Solution (By JKSSB Mock Tests)
Stainless steel is an iron alloy containing at least 10.5% chromium, which provides corrosion resistance by forming a passive chromium oxide layer. Nickel and molybdenum may also be added. Copper and zinc are components of brass. Lead is used in batteries and solder. Chromium is essential for 'stainless' property.
Explanation:
Calorific value is the amount of heat energy produced by complete combustion of unit mass of a fuel. SI unit is J/kg, often expressed as kJ/kg or MJ/kg. Previously, kcal/kg or cal/g was used. 1 cal = 4.184 J. Higher calorific value indicates better fuel. Example: hydrogen has very high calorific value ~150 MJ/kg. Exam note: Calorific value is measured by bomb calorimeter.
Explanation:
Normality (N) is related to molarity (M) by the formula N = M × n, where n is the n-factor (basicity for acids). Sulfuric acid (H2SO4) is a dibasic acid, meaning it can donate two protons (H+) per molecule. Therefore, its n-factor is 2. Normality = 0.1 M × 2 = 0.2 N.
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.
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