Q&A for How to Explain Acids and Bases to Kids

Acids taste sour, feel sticky, and turns litmus paper to red. On the other hand, bases taste bitter, feel slippery, and turns litmus paper to blue.

Acid-Base reaction is a Neutralization reaction. The more reactive metal in a compound displaces the less reactive metal in another compound thus, resulting in the formation of two new compounds. Now, let's take an example: HCl(aq) + NaOH(aq)----> NaCl(aq) + H2O(l). Here, HCl is a dilute acid and NaOH is an alkali (Base dissolved in water). Na is more reactive than H and thus displaces it and forms NaCl(aq). On the other hand, H+ combines with OH- and forms H2O. In general, Acid-Base/alkali reaction can be written as: Acid + Base ----> Salt + Water.

Certain plants, like cabbage, blueberries and poppy petals, contain compounds (anthocyanins) that function as pH indicators . Chop/smash the plant and put them in a bit of water, so the compounds get released into the water. You can the use this solution as a crude pH indicator. Some common indicators used in the lab are universal indicator, phenolphthalein and bromothymol blue.

Theoretically, a substance can have any pH from negative infinity to infinity (with any pH less than 7 being acidic and any pH above 7 being basic). However, most solutions you will find in a standard laboratory fall within the 0-14 range. It is important to note here that the pH scale is logarithmic, not linear. A solution with pH 3 is not twice as acidic as a solution with pH 6; it is actually 1000 times as acidic (10x10x10). Thus, in order to have a pH below 0 or above 14 would require a profoundly acidic or basic solution. In other words, the scale is theoretically (-Infinity, Infinity) but, practically, you only ever see solutions on the 0-14 range.

Organic acids are acids present in plant materials and animals. Some examples are: Citric acid (lemon), lactic acid (curd), tartaric acid (tamarind), oxalic acid (tomatoes), and so on.