Explain what is in a buffer, chemistry homework help

Explain what is in a buffer. Discuss the function of a buffer. How will pH change when small amounts of acids or bases are added to the buffer solution?
Cooks use baking soda to make cakes light and fluffy. You might have used baking soda yourself. Baking soda is NaHCO₃. A 0.1 M solution of baking soda in water has a [H⁺] of about 4.0 × 10^–9. (You may prefer to think of the hydronium ion concentration, [H₃O⁺], as 4.0 × 10^–9.) Write the formula for the calculation of pH, and then show each step as you calculate the pH of a 0.1 M solution of baking soda.

Before tackling this problem, be sure you know how to find the antilog of a number using a scientific calculator.

A solution has a pH of 5.4. Write the formula you will use to calculate the [H⁺] and then show all your work leading to the determination of [H⁺].