310 Domestic Science 



214. Bases react with acids to form a new series 

 of bodies, termed " salts ", water being always simul- 

 taneously produced. Thus, if some sodium hydroxide 

 be added to sulphuric acid until the reaction of the 

 resulting liquid to litmus is neutral, and the liquid be 

 evaporated, a white solid, the salt sodium sulphate, is 

 obtained. 



Sodium hydroxide + hydrogen sulphate 



= sodium sulphate + hydrogen hydroxide. 



215. The characteristic properties of these three 

 groups of compounds, viz. acids, bases, and salts, 

 will next be considered. 



EXPERIMENT 138. Test hydrochloric, sulphuric, 

 nitric, and acetic acids by performing each of the 

 following simple experiments, using in all cases, except 

 where otherwise mentioned, a mixture of the strong 

 acid with about four volumes of water. 



(a) Drop 10 drops of the acid into a beaker half 

 full of water, shake the mixture, and cautiously taste it. 



(6) Put a drop of the acid, taken from the bottle 

 on the end of a glass rod, on a blue litmus paper. 



(c) Into a test-tube, one-quarter filled with the 

 acid, drop a small piece of granulated zinc. Note all 

 that occurs before the action stops entirely. Warm 

 the tube if necessary. 



(d) One-quarter fill a test-tube with acid and 

 drop in about half a gram of powdered copper oxide. 

 Shake well, and hasten the completion of the reaction 

 which occurs by gently heating the tube. 



(e) Similarly treat about half a gram of sodium 

 carbonate. In this case heat will not need to be 

 applied. 



(/) Put a drop of the strongest form of each 

 acid on a filter-paper and allow it to remain for a quarter 



