JNTU Pharm. D I Year PHARMACEUTICAL INORGANIC CHEMISTRY Previous Question Paper (February/March - 2023 - R08)

Accuracy refers to the closeness of a measured value to the true or accepted value. It indicates the correctness of a measurement. Precision refers to the degree of agreement or reproducibility between replicate measurements of the same quantity. It indicates the consistency of the results, regardless of whether they are close to the true value.

Errors in analytical chemistry are generally classified into three main types:

1. Determinate (Systematic) Errors: These errors have a definite cause and can be identified and corrected. They are unidirectional, meaning they consistently bias results either high or low. Examples include instrumental errors (e.g., poorly calibrated weights), methodic errors (e.g., incomplete reactions), and operative errors (e.g., personal bias in reading a meniscus).
2. Indeterminate (Random) Errors: These are accidental and unpredictable errors that arise from uncontrollable variables in the measurement process. They follow the laws of chance or Gaussian distribution, resulting in both positive and negative deviations. They cannot be eliminated but can be minimized by taking the mean of multiple replicate measurements.
3. Gross Errors: These are large, obvious mistakes caused by human error, such as misreading a scale, spilling a sample, or recording a value incorrectly. These errors lead to outliers and require the experiment to be discarded and repeated.