pH A scale for measuring hydrogen ion concentration in a solution, called pH scale has been developed. The p in pH stands for ‘potenz’ in German, meaning power. pH Definition Negative logarithm of the H+ or , H3O+ ion concentration. pH = – log [H+] pH scale : pH colour
Prepare your own indicator i) Crush beetroot in a mortar.ii) Add sufficient water to obtain the extract.iii) Filter the extract by the procedure learnt by you in earlier classes.iv) Collect the filtrate to test the substances you may have tasted earlier.v) Arrange four test tubes in a test tube stand and label them as A,B,C …
The reaction of acids with metal hydrogen carbonates is used in the fire extinguishers which produce carbon dioxide.i) Take 20 ml of sodium hydrogen carbonate (NaHCO3) solution in a wash-bottle.ii) Suspend an ignition tube containing dilute sulphuric acid in the wash-bottle.iii) Close the mouth of the wash-bottle.iv) Tilt the wash-bottle so that the acid from …
Plaster of Paris ( CaSO4 . 1/2 H2O )On heating gypsum at 373 K, it loses water molecules and becomes calcium sulphate hemihydrate ( CaSO4 . 1/2 H2O ). This is called Plaster of Paris ( P.O.P), the substance which doctors use as plaster for supporting fractured bones in the right position. Plaster of Paris …
Copper sulphate crystals which seem to be dry contain water of crystallisation. When we heat the crystals, this water is removed and the salt turns white.If moisten the crystals again with water, you will find that blue colour of the crystals reappears.Water of crystallisation is the fixed number of water molecules present in one formula …
Washing soda (Na2CO3 .10H2O)It can be obtained from sodium chloride isNa2CO3 .10H2O (washing soda). Sodium carbonate can be obtained by heating baking soda; recrystallisation ofsodium carbonate gives washing soda. It is also a basic salt. Na2 CO3 + 10 H2 O → Na2 CO3.10 H2 O Sodium carbonate What does 10H2O signify ? Does it …
Baking soda (NaHCO3 )The baking soda is commonly used in the kitchen for making tasty crispy pakoras, etc. Sometimes it is added for faster cooking. The chemical name of the compound is sodium hydrogen carbonate (NaHCO3 ). It is produced using sodium chloride as one of the raw materials. NaCl + H2 O + CO2 …
Bleaching powder ( CaOCl2 )Chlorine is produced during the electrolysis of aqueous sodium chloride (brine). This chlorine gas is used for the manufacture of bleaching powder. Bleaching powder is produced by the action of chlorine on dry slaked lime [Ca(OH)2 ]. Bleaching powder is represented as CaOCl2, though the actual composition is quite complex. Ca(OH)2 …
Sodium hydroxide ( NaOH )When electricity is passed through an aqueous solution of sodium chloride (called brine), it decomposes to form sodium hydroxide. The process is called the chlor-alkali process because of the products formed– chlor for chlorine and alkali for sodium hydroxide. 2NaCl (aq) + 2H2O(l) → 2NaOH (aq) + Cl2 (g) + H2 …
Common salt — A raw material for chemicalsThe common salt thus obtained is an important raw material for various materials of daily use, such as sodium hydroxide, baking soda, washing soda, bleaching powder and many more. Let us see how one substance is used for making all these different substances.
