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.
Ripe apple guavas (Psidium guajava) Guavas (singular guava, /ËÉ¡wÉË.vÉ/) are common tropical fruits cultivated and enjoyed in many tropical and subtropical regions. Psidium guajava (common guava, lemon guava) is a small tree in the Myrtle family (Myrtaceae), native to Mexico, Central America, and northern South America. Although related species may also be called guavas, they belong to other species or genera, such as the pineapple guava Acca sellowiana.