The statement that is not true about ozone is
a) in the stratosphere, CFCs release free radicals (Cl) which reacts with `O_3` to give chlorine dioxide radicals
b) in the atmosphere, it is depleted by CFCs
c) in the stratosphere, it forms a protective shield against UV radiation
d) it is a toxic gas and its reaction with NO gives `NO_2`

When heathly earth's stratosphere contains a low concentration of ozone (O_(3)) that absorbs potentially harmful ultraviolet (UV) radiations by the cycle shown below: Chloroflouro carbon refrigerants, such as freon 12(CF_(2)Cl_(2)) , are stable in lower atmosphere but in the stratosphere, they absorb high energy UV radiation to generate chlorine radicals. CF_(2)Cl_(2) overset(hv)(to) CF_(2)Cl+Cl The presence of small number of chlorine radicals appears to lower ozone concentrations dramatically. The following reactions are all known to be exothermic (except the one requiring light) and to have high rate constant. A:Cl-O-O-Cloverset(hv)(to)O_(2)+2Cl^(*) B: Cl_O^(*)+O to O_(2)+Cl^(*) C:Cl^(*)+O_(3) to Cl-O^(*)+O_(2) D:2Cl-O^(*) to Cl-O-O-Cl Q. Ozone has the ability to absorb

When heathly earth's stratosphere contains a low concentration of ozone (O_(3)) that absorbs potentially harmful ultraviolet (UV) radiations by the cycle shown below: Chloroflouro carbon refrigerants, such as freon 12(CF_(2)Cl_(2)) , are stable in lower atmosphere but in the stratosphere, they absorb high energy UV radiation to generate chlorine radicals. CF_(2)Cl_(2) overset(hv)(to) CF_(2)Cl+Cl The presence of small number of chlorine radicals appears to lower ozone concentrations dramatically. The following reactions are all known to be exothermic (except the one requiring light) and to have high rate constant. A:Cl-O-O-Cloverset(hv)(to)O_(2)+2Cl^(*) B: Cl_O^(*)+O to O_(2)+Cl^(*) C:Cl^(*)+O_(3) to Cl-O^(*)+O_(2) D:2Cl-O^(*) to Cl-O-O-Cl Q. Inceased UV radiations due to hole in ozone layer:

Write the balanced chemical equations for the following reactions and identify the type of reaction in each case. (a) Iron (III) oxide reacts with aluminium and gives molten iron and aluminium oxide. (b) Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride. (c) Chlorine gas is passed in an aqueous potassium iodide solution to form potassium chloride solution and solid iodine. (d) Ethanol is burnt in air to form carbon dioxide, water and releases heat.

It we see the reaction of methane with halogen, the rate determining step for chlorination is, endothermic reaction of the chlorine atom with methane to form methyl radical and a molecule of HCl. So free radical is the intermediate of the reaction. Formation of free radical depends upon the energy required to break a bond between a hydrogen atom and a carbon atom. Chlorination of propane and Bromination of propane. when compared it is found that bromination is more selective than chlorination. The probability factor for 3^(@),2^(@),1^(@)H atom is 5.0:3.8:1.0 at 25^(@)C for chlorination. Isobutane when reacts with chlorine in presence of ultra violet radiations yield 2 products primary hydrogen substituted and 3^(@) hydrogen substituted Find their % in product mixture

Which of the following statements is not true about glucose? (a)It is an aldohexose (b)On heating with HI it forms n-hexane (c)It is present in furanose form (d)It does not give 2,4-DNP test

Read the following paragraph and answer the questions given below , Stable equilibrium is of various types . Mechanical equilibrium is achieved when all particles are at rest and total potential energy of the system is minimum . At any stage where particles are at rest but the system is not at stable equilibrium as it can reduce its potential energy by reverting to another position, is called metastable equilibrium . Thermal equilibrium is result from the absence of temperature gradients in the system. Chemical equilibrium is obtained when no further reaction occurs between reacting substances, i.e forward and reverse rates of reaction are equal. When steam with solid iron at high temperature Fe_3O_4(s) and hydrogen gas are produced . But the reaction never goes to completion. This is because as the products are formed the reaction proceeds in reverse direction and when rate of reverse reaction is equal to rate of forward reaction , the concentration of reactants and products become constant and equilibrium is reached. When two reactants (A) and (B) are mixed to give products (C) and (D) the concentration quotient (Q) at initial stage of the reaction

Stratosphere contains a stable layer of ozone molecules which absorbs UV radiation from the sun. The presence of ozone in atmosphere serves, as a shield to protect living organism on earth from the harmful effects of the solar ultraviolet radiation. The ultraviolet radiation are known to cause skin cancer. Ozone is formed in stratosphere by the following photochemical reactions. O_(2)(g)overset(UV)rarrO(g)+O(g) O(g)+O_(2)(g)overset(UV)hArrO_(3)(g) Ozone is thormodhynamically unstable and ecomposes to molecular oxygen. Thus a dynamic equilibrium exits between the production and decomposition of ozone molecules. The air pollutant which are responsible to deplete the ozone layer is

Stratosphere contains a stable layer of ozone molecules which absorbs UV radiation from the sun. The presence of ozone in atmosphere serves, as a shield to protect living organism on earth from the harmful effects of the solar ultraviolet radiation. The ultraviolet radiation are known to cause skin cancer. Ozone is formed in stratosphere by the following photochemical reactions. O_(2)(g)overset(UV)rarrO(g)+O(g) O(g)+O_(2)(g)overset(UV)hArrO_(3)(g) Ozone is thormodhynamically unstable and ecomposes to molecular oxygen. Thus a dynamic equilibrium exits between the production and decomposition of ozone molecules. Earth is protected from UV radiation by

Stratosphere contains a stable layer of ozone molecules which absorbs UV radiation from the sun. The presence of ozone in atmosphere serves, as a shield to protect living organism on earth from the harmful effects of the solar ultraviolet radiation. The ultraviolet radiation are known to cause skin cancer. Ozone is formed in stratosphere by the following photochemical reactions. O_(2)(g)overset(UV)rarrO(g)+O(g) O(g)+O_(2)(g)overset(UV)hArrO_(3)(g) Ozone is thormodhynamically unstable and ecomposes to molecular oxygen. Thus a dynamic equilibrium exits between the production and decomposition of ozone molecules. Maximum quantity of ozone is present in

Compound (A), C_(8)H_(6)NOBr , is optically active. Reduction of (A) gives (B) which reacts with nitrouos acid to form (C), dihydric alcohol. Benzene sulphonyl chloride reacts with (B) to give a product soluble in NaOH. Hydrolysis of (A) gives (D) which is an optically active acid. (A) does not give any precipitate with aqueous AgNO_(3) . Controlled oxidation of (A) gives monobromo benzoic acid. Compound (A) on reaction with Br_(2)//Fe gives only one compound. Identify (A), (B), (C), and (D).