Paper: CSIR-NET June 2015 · Subject: Physical Chemistry · Chapter: Data Analysis · Topic: Data Analysis – General · Marks: 2 · Difficulty: Medium
In a conductometric experiment for estimation of acid dissociation constant of acetic acid, the following values were obtained in four sets of measurements. $1.71 \times 10^{-5}, 1.77 \times 10^{-5}, 1.79 \times 10^{-5}$ and $1.73 \times 10^{-5}$. The standard deviation of the data would be in the range of
(a)$0.01 \times 10^{-5}-0.019 \times 10^{-5}$
(b)$0.02 \times 10^{-5}-0.029 \times 10^{-5}$
(c)$0.03 \times 10^{-5}-0.039 \times 10^{-5}$
(d)$0.04 \times 10^{-5}-0.049 \times 10^{-5}$
Answer
Answer: C ✓ checked by 4AB · confidence high
Explanation
Mean 1.75×10⁻⁵; deviations 0.04, 0.02, 0.04, 0.02; s = √(0.0040/3) = 0.037×10⁻⁵, in the range 0.03–0.039 ×10⁻⁵.