chemical properties of carbon compounds( classX)

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combustion, oxidation, addition and substitution

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CHEMICAL PROPERTIES OF CARBON COMPOUNDS:

CHEMICAL PROPERTIES OF CARBON COMPOUNDS 1 Prepared & presented by- Kaushlesh K Sinha Class- 10 th Roll number- 1026

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2 The following are the four chemical properties of carbon compounds : Combustion Reaction(by all types of hydrocarbons) Oxidation reaction(by all types of hydrocarbons) Addition reaction(Unsaturated hydrocarbon) Substitution reaction(Saturated hydrocarbon)

COMBUSTION REACTION:

COMBUSTION REACTION Combustion is the burning of any compound in sufficient supply of oxygen. It is an exothermic process as heat and light energy is liberated. Alkanes ( eg -methane) burn to give lot of heat, so they are good fuels. 3 During the combustion of any organic compound the products will definitely be water( H 2 O ) and carbon dioxide(CO 2 ). Eg: C 2 H 6 + 7/2 O 2 3H 2 O + 2CO 2 + heat + light CH 4 + 2O 2 2H 2 O + CO 2 + heat + light C 2 H 5 OH + 3O 2 3H 2 O + 2CO 2 heat + light

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4 HOW DO DIFFERENT HYDROCARBONS BURN? HYDROCARBON IN LIMITED (INSUFFICIENT) SUPPLY OF AIR IN REQUIRED SUPPLY OF (PURE) OXYGEN SATURATED Sooty Flame Produces black smoke Blue colored flame Non-sooty flame No smoke produced As they have lesser % of carbon, which gets oxidized completely. UNSATURATED Yellow colored flame Sooty flame Produces black smoke Blue colored flame Non-sooty flame No smoke As they have a comparatively higher % carbon that doesn’t oxidize completely.

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5 The gas stoves in our home has tiny holes to allow sufficient air to enter thus allowing complete combustion of LPG. This produces blue, smokeless flame that doesn’t harm the vessels. However if these holes are blocked less air is available causing incomplete burning of LPG that would blacked the vessel surface and also cause wastage of fuel. {LPG contains Butane}. While coal and petroleum contain small amount of nitrogen and sulfur that form oxides on combustions. These oxides pose threat to the environment. Acetylene( ethyne ) when burnt simply doesn’t produce heat but a sooty flame. But when Acetylene is mixed with oxygen and burnt it produces extremely hot flame. This acetylene-oxygen mixture is used for welding metals Blackened vessel. Welding of metal Smokeless blue flame

OXIDATION REACTION:

OXIDATION REACTION 6 During the oxidation of any carbon compound in the presence of oxidizing agent new products are formed, i.e. the functional group of the carbon compound is changed. Oxidizing agents: Nitric Acid (HNO 3 ) (Alkaline)Potassium Permanganate( KMnO 4 ) (Acidic)Potassium Dichromate (K 2 Cr 2 O 7 ) Oxidaion C 2 H 5 OH CH 3 COOH Ethanol K 2 Cr 2 O 7 or KMnO 4 Ethanoic acid Ethanol belongs to alcohol group. After oxidation it changes into the carboxylic acid group. Combustion requires oxygen to occur. However combustion and oxidation are different. In combustion the products are constant( water and carbon dioxide), but during oxidation new products are formed, i.e. the functional group of the carbon compound is changed. Moreover oxidation of a carbon compound also requires presence of any oxidizing agent.

SUBSTITUTION REACTION:

SUBSTITUTION REACTION 7 During a substitution reaction one atom or group replaces another atom or group. More specifically a reaction in which one (or more)hydrogen atom of the carbon compound is replaced by one(more) atoms of another element is called substitution reaction. Though saturated hydrocarbons are quite unreactive and inert they undergo substitution with chlorine in presence of sunlight. In the whole process the bond arrangement of the reactant and the product should be same. Methane undergoes substitution reaction with chlorine in the presence of sunlight to form substitution products, as shown below-

ADDITION REACTION:

ADDITION REACTION 8 In an addition reaction an unsaturated hydrocarbon gets saturated by the addition of hydrogen, halogen, acid, etc. Unsaturated hydrocarbon on reacting with hydrogen forms a saturated hydrocarbon. This type of reaction is called addition reaction. Ni or Pd catalyst C 2 H 4 + H 2 C 2 H 6 H H H H I I Ni or Pd catalyst I I C = C + H 2 H – C – C – H I I I I H H H H The addition of hydrogen to unsaturated hydrocarbons to form saturated hydrocarbons is called hydrogenation. Hydrogenation is used to convert unsaturated oils and fats to saturated oils and fats. These saturated oils and fats are nothing but the ones we know as ghee. Actually these saturated oils and fats are said to be harmful to health. So it is advised to use unsaturated oil for cooking.

Flashback…:

Flashback… 9 Q1) What is Bromine water? What is its color? What is its use? Explain.[Look at the figure on top left of the slide] Q2) Which of the following hydrocarbon undergo addition reaction, and which ones undergo substitution reaction? Also tell the name of the compound. a) C 2 H 6 b) C 3 H 8 c) C 3 H 6 d) C 2 H 2 Q3)What is the pH of the following compounds likely to be: a) HNO 3 b) KMnO 4 Q4) Name any two elements that are present in coal and petroleum(in small amount) and form oxides that pose threat to the environment on combustion. Q5) Why is ethyne in its general form not used for welding metals? Q6) Why is the of ethanol into ethanoic acid called an oxidation reaction?

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10 THANKYOU