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4.5 g of a compound A (molar mass = 90 g/mol) is dissolved to make 250 mL of aqueous solution. If the molarity of the solution is x * 10⁻¹ M, find the value of x (rounded to the nearest integer).

1. 1
2. 2
3. 5
4. 9

Correct answer: 2

Solution

The molarity is 0.2 M = 2 * 10⁻¹ M, so x = 2.

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