Determine the pHpH of an HFHF solution of each of the following concentrations. In which cases can you not make the simplifying assumption that xx is small? (KaKa for HFHF is 6.8×10−46.8×10−4.)

The question is incomplete, complete question is :

Determine the pH of an HF solution of each of the following concentrations. In which cases can you not make the simplifying assumption that x is small? ( for HF is .)

[HF] = 0.280 M

Express your answer to two decimal places.

The pH of an 0.280 M HF solution is 1.87.

Explanation:3

Initial concentration if HF = c = 0.280 M

Dissociation constant of the HF =

Initially

c          0            0

At equilibrium :

(c-x)      x             x

The expression of disassociation constant is given as:

Solving for x, we get:

x = 0.01346 M

So, the concentration of hydrogen ion at equilibrium is :

The pH of the solution is ;

The pH of an 0.280 M HF solution is 1.87.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.