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JEE Main levelSingle correct optionDifficulty 2 of 3sc180

The gold numbers of gelatin, gum arabic and potato starch are 0.01, 0.15 and 25 respectively. Which statement is correct?

  1. AStarch is the best protective colloid; gelatin must be used in 2500 times the mass of starch for the same protection
  2. BGelatin is the best protective colloid; starch must be used in 2500 times the mass of gelatin for the same protection
  3. CStarch is the best protective colloid; gelatin must be used in 0.04 times the mass of starch for the same protection
  4. DGelatin is the best protective colloid; starch must be used in 25 times the mass of gelatin for the same protection

Answer: B

A smaller gold number means better protection, so gelatin (0.01) is the best. The mass ratio for equal protection is , so starch is needed in 2500 times the mass of gelatin.
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