The Lime-Soda Process Is Used for Large-Scale Water-Softening Operations

question 117

Multiple Choice

The lime-soda process is used for large-scale water-softening operations. CaO is added to __________.

• A)oxidize Fe²⁺ to insoluble Fe₂O₃
• B)cause precipitation of magnesium as Mg(OH)₂
• C)remove most Al³⁺ as solid Al(OH)₃
• D)cause precipitation of iron and magnesium as Fe₂MgO₄
• E)reduce the pH to 3-4

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Definitions:

Z-axis

The axis in a three-dimensional coordinate system representing the depth, perpendicular to both the X-axis (horizontal) and Y-axis (vertical).

Standard Deviations

A metric indicating the extent of variability or spread in a collection of values, denoting how far away the values deviate from the average.

Standard Normal Distribution

A type of normal distribution where the mean is 0 and the standard deviation is 1, used in statistics for z-score calculations.

Variance

A statistical measurement of the dispersion or spread of a set of data points, indicating how much the individual data points differ from the mean.