At the other extreme, a 10 M solution of NaOH would have a pH of 15. Numerical examples from Shipman, Wilson and Todd. In pure water, the molar concentration of H + ions is 10-7 M and the concentration of OH-ions is also 10-7 M.
In order to tell if a guava is ripe, squeeze it gently. If it gives under your fingers, its ripe. 2. Look for any blemishes on the guava. You want to try to select guavas that are blemish-free. Blemishes or bruises can mean the fruit is bad or will not taste good. 3. Check the color of the guava. Ripe guavas are those that have gone from bright green to a softer yellowish-green color. If you see a touch of pink on the fruit, it is in its prime. If you don't find any that are yellow, you can always buy green guava and wait for them to ripen.
Guava leaves contain both carotenoids and polyphenols like (+)-gallocatechin and leucocyanidin. As some of these phytochemicals produce the fruit skin and flesh color, guavas that are red-orange tend to have more polyphenol and carotenoid content than yellow-green ones.n many countries, guava is eaten raw, typically cut into quarters or eaten like an apple, whereas in other countries it is eaten with a pinch of salt and pepper, cayenne powder or a mix of spices (masala) . It is known as the winter national fruit of Pakistan.