How many moles of solid NaF would have to be added to 1.0 L of 0.115 M HF solution to achieve a buffer of pH 3.46? Assume there is no volume change. Ka for HF = 7.2 × 10 –4

Answer : The  moles of solid NaF is, 1.09 mole.

Explanation : Given,

pH = 3.46

Concentration of HF = 0.115 M

Volume of solution = 1.0 L

First we have to calculate the value of .

The expression used for the calculation of is,

Now put the value of in this expression, we get:

Now we have to calculate the moles of HF.

Now we have to calculate the moles of NaF.

Using Henderson Hesselbach equation :

Now put all the given values in this expression, we get:

Thus, the moles of solid NaF is, 1.09 mole.

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

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conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.