A 1000-ML Sample of 0 $\times$ 10^-10
B)4 $\times$ 10^-5
D)not Enough Information to Calculate
E)none of These

question 10

Multiple Choice

A 100.0-mL sample of 0.503 M H₂A (diprotic acid) is titrated with 0.200 M NaOH.After 125.0 mL of 0.200 M NaOH has been added,the pH of the solution is 4.50.Calculate K_a1 for H₂A.

• A)3.2 \(\times\) 10^-10
• B)4.5
• C)3.1 \(\times\) 10^-5
• D)not enough information to calculate
• E)none of these

---

Definitions:

Weighted Average

An average resulting from the multiplication of each component by a factor reflecting its importance.

Z-score

A numerical metric indicating how a particular value compares to the average of a dataset, expressed by the number of standard deviations it lies from the mean.

P-value

The likelihood of encountering experimental results that are at least as significant as the actually observed results, given the null hypothesis is assumed to be accurate.

Pooled Variance

A method used in statistics to combine variances from two or more groups to estimate a common variance when they are assumed to be equal.