Understand the preparation of Hydrogen Sulphide. Click on the link to Watch the VIDEO explanation: Watch Video
The apparatus is arranged in the Video. A few pieces of iron Sulphide are taken in the round bottom flask. Dilute HCl acid is poured into it until the lower part of thistle funnel is covered by the acid. Reaction takes place and hydrogen sulphide gas evolved. This gas is collected in the gas jar through upward displacement of air.
Understand Isomerism in pentane. Click on the link to Watch the VIDEO explanation:
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With the molecular formula C5H12 there are three isomers possible. With all the five carbon atoms are lined in a linear fashion this isomer called n-pentane. IUPAC name is pentane. When a methyl group is shifts and attachés to the second or the third carbon atom it forms iso-pentane. And IUPAC name is 2-methyl butane. Observe the neo pentane there are two methyl groups one above and one low attached the second carbon atom. This compound name is 2,2-dimethyl propane in the IUPAC nomenclature.
Understand Isomerism in Butane. Click on the link to Watch the VIDEO explanation:
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The molecular formula in butane is C4H10. With this molecular formula there are two arrangements possible. The first shows all the carbon atom in a linear chain. Shown here is normal butane. When one methyl group detaches from chain and join the 2nd carbon atom 2 methyl propane is formed. This is called iso butane in common nomenclature.
Understand the dehydrating property of conc. sulphuric acid. Click on the link to Watch the VIDEO explanation: Watch Video
Sulphuric acid has a great affinity for water. Lets understand it with an experiment. For this you will need beaker, cane sugar, water, spatula, conc. H2SO4 and droppers. Take a spatula of cane sugar in a beaker. Add a small amount of water into the beaker. Now slowly add conc. H2SO4 into the beaker containing sugar. The mixture starts frothing because of the heat being generated by this exothermic reaction. The black mass formed is pure amorphous carbon called as sugar charcoal. Sugar is a carbohydrate, a water and carbon compound. Stream that formed rises up creating the bubbles. Conc. H2SO4 takes away water from sugar and left behind is pure carbon. Due to the same reason it is highly corrosive on skin because it breaks down protein molecules of which skin is made of and takes away the water. Conc. H2SO4 removes water from many organic substances like sugar, paper, wood etc. It is therefore a dehydrating agent.
Understand common Test to differentiate hydrocarbons. Click on the Link to Watch the VIDEO explanation: Watch Video
Hydrocarbons are compounds of Hydrogen and Carbon. They may be unsaturated or saturated. A saturated hydrocarbon can be separated from a unsaturated one by using bromine dissolved in carbon tetrachloride, alkaline potassium permanganate and Ammoniacal cuprous chloride or by ignition test. You can perform these test yourself. Before you start performing the test you need to understand how to perform. Here is how. On the reagent rack there are three bottles labelled 1, 2 and 3 containing Bromine solution, alkaline potassium permanganate and ammoniacal cuprous chloride. These are the reagents that you need to testing the hydrocarbons. Here is a match box. You are provided with two sets of three gas jar each labelled A, B, and C which contain three types of hydrocarbons alkane, alkene and alkyne. Chose one reagent at a time. Drag and drop the reagent into all the three gas jars placed on left and observe the changes. Do the same with all the three reagents. Then click on the matchbox and drag the match stick into all the three gas jar placed on right. Observe the changes. key in your inference here.
Understand the Bleaching action of sulphur dioxide. Click on the Link to Watch the VIDEO explanation: Watch Video
Sulphur dioxide access is a bleaching agent and bleaches vegetable colouring matter in presence of moisture. You can observe here how moist flower looses colour. The bleaching action sulphur dioxide is due to its reducing action. The colour of pigment on exposure to SO2 gets reduced to a colourless compound. On standing in an air the colourless reduced product is reoxidised and gain the original colour. Bleaching with sulphur dioxide is therefore of temporary nature. It is generally used for bleaching delegate article like ivory, silk, wool etc.
Understand preparation of sulphur dioxide in laboratory. Click on the Link to Watch the VIDEO explanation: Watch Video
The apparatus required for the preparation of sulphur dioxide in the laboratory is shown here. Copper turnings are taken into the flask. Conc. sulphuric acid is poured into the thistle funnel until it covers the copper turnings. The flask is gently heated. Reaction takes place and sulphur dioxide is liberated in a continuous stream. Sulphur dioxide being heavier than air is collected in a gas jar by upward displacement of air.
Understand Catenation in carbon. Click on the Link to Watch the VIDEO explanation:
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Here you can see linear chain of carbon. Likewise you can see branched chain of carbon and this is a ring structure of carbon. Catenation is the property of atoms of the same element to link with one another covalently, forming linear chain, branched chain or ring. Catenation in carbon atom is responsible for the presence of innumerable compounds of carbon.
Understand Fountain experiment of ammonia. Click on the Link to Watch the VIDEO explanation: Watch Video
The apparatus required for the interesting experiment is arranged as shown here. Red litmus solution is taken into lower flask while the upper one contains ammonia gas. When air is blown into lower flask high pressure is created in the flask due to high pressure the red litmus solution is sucked into the upper flask then red litmus solution's colour immediately changed into blue colour and comes out in the form of Fountain through the jet tube. Ammonia is basic in nature and is highly soluble in water that is the reason the colour of solution changes to blue.
Understand the process of Catalytic oxidation of ammonia. Click on the link to Watch the VIDEO explanation: Watch Video
In the presence of platinum at 800 °C ammonia reacts oxygen to form nitric oxide which can be used as a starting substance for the preparation of nitric oxide. This is an industrial process the principle for which can be demonstrated in laboratory. The apparatus required for the laboratory demonstration of this process is shown here. The platinum coil is heated at 800 °C till it becomes white hot. Then ammonia and oxygen are passed through the combustion tube. Under these conditions ammonia reacts with oxygen to form nitric oxide and water vapour. As nitric oxide and nitrogen monoxide comes out in the air it cools down and combines with the oxygen of air to form reddish brown nitrogen dioxide. This NO2 is used to prepare Nitric Acid in presence of water and oxygen as per the equation shown here.
Understand the preparation of Ammonia. Click on the Link to Watch the VIDEO explanation: Watch Video
The test tube containing a mixture of ammonium chloride and calcium hydroxide is heated. After sometime ammonia gas is evolved. The gas is passed through the lime tower where the moisture is removed. Drying is necessary because water vapour is one of the product formed. Ammonia gas being highly soluble in water has to be dried quickly to prevent from dissolving. Dried ammonia gas being lighter than air is collected upward in the jar by downward displacement of air. Calcium chloride is left in the test tube. A moist red litmus paper is used check presence of ammonia in the gas jar. The red litmus paper turns blue because ammonia is basic.
Understand the process of Distillation of Coal Tar. Click on the Link toWatch the VIDEO explanation: Watch Video
Water mixed with coal tar is completely removed before carrying distillation. For distillation coal tar is introduced in a pre heater provided with a set condensing coils. These coils carry out the hot vapours from the furnace. As a result of the heat of the pipe the water present in the coal tar is evaporated. Some low boiling hydrocarbon are also removed with the help of condensing coils immersed in water. The dehydrated tar is then taken in a vertical furnace as shown. On heating the various product get collected in the receivers at specific temperature. In order to prevent the formation of coke steam is regularly passed into the chamber.
Understand How NaOH reacts with Litmus solution, Aluminum metal and HCl. Click on the Link to Watch the VIDEO explanation: Watch Video
Lets observe how NaOH reacts with Litmus solution, Aluminium metal and HCl. Click on the titles to view the animation. Aluminium reacts with NaOH to liberate hydrogen gas and forms salt sodium aluminate. It is for this reason that aluminium containers are not used to store alkalise. There is neutralisation reaction between NaOH and HCl giving common salt and water as product.
Understand difference between Structure of Diamond and Graphite. Click on the link to Watch the VIDEO explanation: Watch Video
Diamond and Graphite are allotropic forms of carbon widely differing in their physical appearance as can be seen here. Diamond has unmatched brilliance while graphite is dull and lack lustre. The core of pencil is made of graphite. Observe the diagrammatic view of the molecular structure of diamond and graphite. The diamond crystals found in nature are made of tetrahedron units. In diamond carbon atoms are strongly bound to each other. Each carbon atom is bond to four other carbon atom forming a rigid 3D structure. This strong bonding in diamond is the reason for its hardness, resistance to chemical attacks and high density. Diamond is a non conductor of electricity as there are no free electrons to migrate. Graphite on the other hand are cousin hexagonal layer stacked one on the top of the other. In graphite each carbon atom is bound to three other carbon atom. Carbon atoms arrange themselves into layers and between each layer the bonding is very weak. The layers can therefore easily slip over each other. This explains why the surface of graphite is soft and slippery to touch. Click ahead for differences between diamond and graphite.
Understand How dilute HCl reacts with Litmus solution, Zinc metal, Sodium carbonate and sodium hydroxide. Click on the link to Watch the VIDEO explanation:
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Lets observe how dil. HCl reacts with Litmus solution, Zinc metal, Sodium carbonate and sodium hydroxide. Click on the title to view the animation. Zinc displaces hydrogen from dil HCl and forms zinc chloride. HCl reacts with sodium carbonate with the evolution of CO2. NaCl and water are other products. What you saw was a neutralisation reaction between HCl and NaOH. The products are NaCl and water.
Understand acid reaction with alkaline and Neutralisation reaction. click on the link to Watch the VIDEO explanation: Watch Video
Take 5ml of dil. NaOH solution in beaker and add few drop of Phenolphthalein and stir it well with a glass rod. Solution colour turns into Pink colour. Add few drop of Dilute HCl in beaker as shown here. See if any change in colour in the beaker.
Understand pH scale. Click on the link to Watch the VIDEO explanation:
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Historical Background of pH scale. Read on for more. The pH values of common substances range from 0 to 14. The value of 7 on pH scale is Neutral. Pure water and all aqueous solutions with pH equal to 7 at 25 degree Celsius are neutral. If less than 7 in pH scale a given solution is acidic and if the pH is more than 7 it is basic. Note: keep in mind that because pH is on a logarithmic scale, every unit change in pH represents a tenfold change in hydronium ion concentration, thus, lemon juice is approximately ten times as acidic as orange juice and about 100 times more acidic than tomato juice. pH of a given substance can be measured using pH meters or indicator papers.
Understand the action of Indicators on Acid and Bases. Click on the link to Watch the VIDEO explanation: Watch Video
Here are four bottles labelled A, B, C, and D. Each containing the indicators Methyl Orange, Phenolphthalein, Blue Litmus and Red Litmus. Here are six test tube containing samples listed on right hand side.
Understand oxygen reacts with non metals. Click on the link to Watch the VIDEO explanation: Watch Video
Place a small piece of phosphorous on a china dish. Burn the phosphorus with the help of glowing splinter. Cover it with an inverted gas jar. You look the gas jar gas filled with white fumes. Make the gas jar up right and pour some water in the jar and shake well. White fumes dissolve in water. Now put some slue litmus solution into the gas jar. The colour of litmus changes into red. It shows oxide of phosphorus is acidic in nature. This experiments proved Non-metallic oxides are acidic in nature.
Understand Frasch process for extraction of sulphur. Click on the link to Watch the VIDEO explanation: Watch Video
It is based on the fact that sulphur has a comparatively low melting point. The Frasch pump consisting of three concentric pipe is sunk deep into sulphur bed. Super heated water in pumper under pressure in outer most pipe. This melts the sulphur present in the sulphur bed. Compressed air is pumped in the inner most pipe. This forces the mixture of water and molten sulphur to rush out through the middle pipe. This mixture of molten sulphur is collected. On cooling about 99% pure sulphur get separated.
Understand Polar Covalent Bonding. Click on the link to Watch the VIDEO explanation: Watch Video
The molecule HCl is formed by sharing of electrons between a hydrogen atom and a chlorine atom. Hydrogen has 1 electron in the valence shell while chlorine has 17. Chlorine being more electronegative than hydrogen, the shared electron is pulled closer to chlorine. So chlorine atom get a small negative charge called as d- and hydrogen atom gets a small positive charge called as d+.
Understand process of combustion of hydrogen gas. click on the link toWatch the VIDEO explanation: Watch Video
To prove the property of combustion of hydrogen we need to prepare of hydrogen gas in the laboratory. Zinc granules are taken in a woulf's bottle and the apparatus is arranged as shown here. Dilute Sulphuric acid is dropped into the woulf's bottle through the thistle funnel. Hydrogen gas evolved is pass through U-tube containing calcium chloride. Calcium chloride absorbs the moisture present in Hydrogen. Now what happen when a glowing splinter is brought near the gas coming out through the tube. The gas burns with a pale blue flame with a pop sound. Arrange a setup for circulating cold water. Bring this flame near the flak in which cold water is constantly circulated. Some water droplets are collected at the upper of the flask. This experiment shows that water is formed when hydrogen is burnt in air.
Understand Hydrogen is lighter than air. click on the link to Watch the VIDEO explanation: Watch Video
To prove that Hydrogen is Lighter than Air we need to prepare to hydrogen gas in the laboratory. Zinc granules are taken in the woulf's bottle and the apparatus is arranged shown here. Dilute Sulphuric acid is dropped into woulf's bottle through the thistle funnel. The hydrogen gas formed is made to pass through the caustic soda solution so that it becomes free form acid and the gas is passed through the soap solution taken the trough. What you observe. You will find that the bubble of hydrogen formed rise upward like balloons. This shows the gas present in bubbles is lighter than air.
Understand Ionic Bond. Click on the link to Watch the VIDEO explanation: Watch Video
An ionic bond is an electrical attraction between two oppositely charged atoms or group of atoms. Normally atoms are neutral and have no charge. However in order to gain stability they sacrifice their neutrality by losing one or electrons from their outer most shell. Thus becoming Positive ion, cation. Or gaining one or more electron to become negative ion, anion. Elements that are described as metallic tend to lose electron and non metallic elements tend to gain electron. Once this is happened then the resulting charged atoms will attract each other. That electrical attraction is referred to as ionic bond.
