2. HYDROGEN WAS DISCOVERED IN 1766 BY CAVENDISH HE ALSO PROVED THAT IT IS AN ELEMENT. LAVOISIER NAMED IT AS HYDROGEN. THE WORLD HYDROGEN MEANS “ WATER GENERATING GAS. ’’CAVENDISH HYDROGEN IS FOUND IN NATURAL GASES IN A SMALL QUANTITY AND THE SUN IS ALMOST ENTIRELY MADE UP OF HYDROGEN. HYDROGEN IS PRESENT IN WATER,ACIDS,BASES AND PETROL. IT IS FOUND ALONG WITH CARBON IN A LARGE NUMBER OF ORGANIC COMPOUNDS.

3. 1 2 3 4 5 6 THISTLE FUNNEL - 1 DELIVERY TUBE - 2 TWO HOLED RUBBER CORK – 3 * GAS JAR - 4GAS JAR - 4 * WATER - 5 * ROUND BOTTOMED FLASK - 6

4. HYDORGEN IS PRERPARED IN THE LABORTORY WHEN GRANULES OF ZINC REACT WITH COLD DILUTE SULPHURIC ACID. SET UP THE APPARATUS AS SHOWN IN THE FIGURE. TAKE SOME GRANULS OF ZINC IN A ROUND BOTTOMED FLASK. ADD DILUTE SULPHURIC ACID THROUGH THE THISTLE FUNNEL. THE TIP OF THE THISTLE FUNNEL SHOULD BE IMMERSED IN SULPHURIC ACID INVERT A GLASS JAR CONTAINING WATER ON A BEEHIVE SHELF. HYDROGEN IS EVOLVED WHEN ZINC REACT REACTS WITH SULPHURIC ACID. HYDROGEN GETS COLLECTED IN THE JAR BY THE DOWNWARD DISPLACEMENT OF WATHER. –ZINC+SULPHURI ACID ZINCSULPHATE+HYDROGEN ZN +H SO ZNSO + H HYDROGEN + OXYGEN WATER 2H + O 2H O HYDROGEN + CHLORINE HYDROGENCHLORIDE H + CL 2HCL

5. (1) OBSERVE THE COLOUR OF HYDROGEN AND SMELL THE JAR CONTAINING HYDROGEN. DO YOU SEE ANY COLOUR ? NO. DO YOU SMELL ANY ODOUR ? NO. FROM THIS YOU KNOW THAT HYDROGEN IS A COLOURLESS ANDODOURLESS GAS. HYDROGEN IS A COLOURLESS AND ODOURLESS GAS (2) INVERT AN EMPTY JAR OVER AJAR CONTAINING HYDROGEN AND REMOVE THE GLASS COVER. INTRODUCE A BURNING CANDLE INTO THE UPPER JAR. YOU WILL OBSERVE THE GAS BURNING WITH A POP SOUND. THIS SHOWS THAT THE GAS GOES TO THE UPPER JAR QUICKLY FROM THE LOWER JAR. FROM THIS WEE UNDERSTAND THAT HYDROGEN IS LIGHTER THAN AIR.

6. CHEIMCAL PROPERTIES CHEIMCAL PROPERTIES OF HYDROGEN HYDROGEN CHEIMCAL PROPERTIES HYDROGEN (1)INVERTA A JAR CONTAINING HYDROGEN. INTRODUCE A BURNING CANDLE INTO IT. HYDROGEN GAS BURNS WITH A POP SOUND AND THE CANDLE GETS EXTINGUISHED.SMALL WATER DROPS ARE SEEN ON THE INNER WALLS OF THE JAR. HYDROGEN AND OXYGEN UNITTE WITH ‘POP’ SOUND AND PRODUCE WATER. (2)PLACE A JAR OF HYDROGEN AND A JAR OR CHLORINE SIDE BY SIDE IN BRIGHT SUNLIGHT AND REMOVE THERE LIDS. THE TWO GASES REACT WITH EXPLOSION AND PRODUC A PUNGENT SMELLING GAS IS CALLED HYDROGEN CHLORIDE. (3)HYDROGEN AND NITROGEN COMBINE AT VERY HIGH PRESSURE IN THE PRESENCE OF MOLYBDENUM- IRON CATALYAST AND GIVE AMMONIA.THIS IS CALLED HABER’S PROCESS.