Question 4: Give 3 test tubes, each containing 5ml of distilled water, numbered (1), (2), (3). – Using identical spoons each scoop one of the following powdered solids: urea (protein fertilizer), sugar, and powdered chalk into the respective test tubes and mix well. – In tube (1), on the 5th spoon, urea could not dissolve any more, we saw solid powder deposited at the bottom of the test tube. – The same phenomenon in tube (2) occurs when the sugar reaches the 10th spoon; In tube (3), from the first spoon of chalk powder did not dissolve completely. Which of the following substances is the least soluble in water?

Question 4: Give 3 test tubes, each containing 5ml of distilled water, numbered (1), (2), (3). – Using identical spoons each scoop one of the following powdered solids: urea (protein fertilizer), sugar, and powdered chalk into the respective test tubes and mix well. – In tube (1), on the 5th spoon, urea could not dissolve any more, we saw solid powder deposited at the bottom of the test tube. – The same phenomenon in tube (2) occurs when the sugar reaches the 10th spoon; In tube (3), from the first spoon of chalk powder did not dissolve completely. Which of the following substances is the least soluble in water?

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