Given that the k sp for caf2 at 25°c is 3.9 × 10–11, will a precipitate form when 0.10 l of 2.3 × 10–4 m cacl2 is added to 0.50 l of 5.0 × 10–3 m naf? assume volumes are additive.

- Precipitate will form.

Solution:- A precipitate is formed if the ionic product is greater than solubility product,  ( )

0.10 L of calcium chloride and 0.50 L of sodium fluoride are added. So, total volume of the solution = 0.10 L + 0.50 L = 0.60 L

We get the calcium ions from calcium chloride as:

From this equation, there is 1:1 mol ratio between calcium chloride and calcium ion. So, the initial concentration of calcium ion will be same as of calcium chloride. As the volume is additive, the final concentration of calcium ion is calculated using the dilution equation:

It could also be written as,  

Let's plug in the values in it:

Similarly there is 1:1 mol ratio between sodium fluoride and fluoride ions. we can calculate the final concentration of Fluoride ion as:

Now, we will calculate the ionic product as:

Given solubility product is which is less than the calculated value of ionic product.  ( ) .

Hence. the precipitate will form.

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.