The ph of coffee is 5.6. the ph of grapefruit juice is 2.6. this means that the proton concentration in coffee is

pH scale is used to measure the acidity or alkalinity on a scale of 0-14 where 0-6.9 is the acidic region , 7.1-14 is the basic region and 7 is for the neutral substance. We can calculate the concentration of proton from pH.

where is the concentration of proton

As per the question ,the pH of coffee is 5.6 and we need to find the concentration of proton so putting the values in the above equation, we get

i think it is true since you can test the answer and can use observations to complete it.

it is the most commonly accepted one