Acids, Bases and buffers

Question 1

What is the main buffer in saliva

Answer 1

Bicarbonate HCO-3
Phosphate and protein also contribute to its buffering capacity

Question 2

What are the three pH ranges of phosphate

Answer 2

H3PO4  H+ + H2PO4- pKa = 2.16​

H2PO4-  H+ + HPO42- pKa = 7.21​

HPO42-  H+ + PO43- pKa = 12.32​

Question 3

How is the pH of blood maintained

Answer 3

Blood is maintained at pH 7.4 by bicarbonate and protein buffers​

Cells require pH in the cytoplasm and organelles to be closely controlled to preserve enzyme and membrane function​

Question 4

When do buffers have greatest buffering capacity

Answer 4

When 50% dissociated pKa = pH

Question 5

What is pH

Answer 5

A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid and higher values more alkaline. The pH is equal to −logx, where x is the hydrogen ion concentration in moles per litre.

Question 6

What causes tooth erosion

Answer 6

Tooth erosion is caused by the direct effect of acids in the diet on teeth​ such as fizzy drinks

Organic acids such as citric acid bind to calcium ions which can then no longer counteract calcium solubilisation leading to tooth erosion also