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Question #44652

Difficulty: 8/10 | 🟢 Free

The Question

A standardized aqueous solution of \ce{NaF} has a measured concentration of 0.0120.012 M. At 298 K, the solubility of \ce{BaF2 (s)} in this solution is analytically determined to be 2.2×10−32.2 \times 10^{-3} M. Assuming ideal behavior, calculate the solubility product constant (KspK_{sp}) of \ce{BaF2} at 298 K, reported to the correct number of significant figures.

Options

  • A.

    5.6×10−75.6 \times 10^{-7}

  • B.

    5.9×10−75.9 \times 10^{-7}

  • C.

    4.3×10−74.3 \times 10^{-7}

  • D.

    3.2×10−73.2 \times 10^{-7}

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Numerical_Precision

Improve calculation stamina and avoid rounding errors in high-stakes competitive examinations.

Concepts Behind This Question

Significant Figures in Arithmetic|Common Ion Effect on Solubility

Why This Question Is Tricky

Common Mistakes

This question tests the rigorous application of significant figure rules during mixed mathematical operations within a Common Ion Effect context.

The 'Hidden Trap' lies in the intermediate addition step: [\ceF−]=0.012+0.0044=0.0164[\ce{F^-}] = 0.012 + 0.0044 = 0.0164 M.

Students often blindly plug unrounded intermediate values into the KspK_{sp} expression.

However, according to the rules of significant figures, addition is governed by the least number of decimal places.

Since 0.0120.012 has three decimal places, the sum must be rounded to 0.0160.016 M before squaring.

Failing to round during this addition step yields the incorrect distractor 5.9×10−75.9 \times 10^{-7}.

Quick Facts About This Question

Question Information

SubjectChemistry
ChapterSome Basic Concepts of Chemistry - Class 11 Part 1
ConceptSignificant Figures in Arithmetic
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree