Identify the correct statement.
Gypsum contains a lower percentage of calcium than plaster of Paris
Gypsum is obtained by heating plaster of Paris
Plaster of Paris can be obtained by hydration of gypsum
Plaster of Paris of obtained by partial oxidation of gypsum

Identify the correct statements., (i) Winter smog is reducing in nature due to presence of particular carbon and SO_(2) (ii)The pollutant obtained from emission tubes of diesel engines is benzopyrene. (iii) Photochemical smog is made up of PAN , O_(3) and oxides of nitrogen (iv) CFCs are stable in troposphere and act as pollutants in stratosphere

A small amount of CaCO_(3) completely neutralises 525 mL of 0.1 N HCl and no acid is left in the end. After converting all calcium chlorine to CaSO_(4) , how much plaster of Paris can be obtained ?

Assertions: In an exothermic reaction ,a greater yield of products can be obtained by lowering the temperature. Reason: In an exothermic reactions , the heat constant of reactants is greater than that of the products.

Cement is one of the most important building material of the present time. It is a dirty greyish heavy powder containing calcium aluminates and silicates. The important raw materials neede for the manufacture of cement are limestone, clay and gypsum. the main step in the manufacture of cement is the heating of raw meal or slurru in the rotary kiln at a very high temperature 1400-1600^(@)C . Finally 2% or 3% gypsum is added. When cement is mixed with water and left as such for sometime, it becomes a hard mass. This is known as setting of cement. It is believed that varous aluminates and silicates present in the cement form hydrates with water which seperate in the form of gel. the gel formed start losing water partly by evaporation and partly by forming hydrates with unhydrated constituents. this results in the formation of a hard mass. Gypsum is added to portland cement

An organic compound (A) having C = 16.27%,H = 0.677%, Cl = 72.203% reduces Fehling solution and on oxidation gives an acid (B) having C = 14.679%, H = 0.612% and Cl = 65.137%. (B) on distillation with sodalime gives a sweet smelling liquid (C) which contains 89.12% chlorine. (C) can also be obtained by heating (A) with alkali. (A) can also be obtained by the action of Cl2 on C_2 H_5 OH . Identify (A), (B) and (C) and explain the reactions.

Cement is one of the most important building material of the present time. It is a dirty greyish heavy powder containing calcium aluminates and silicates. The important raw materials neede for the manufacture of cement are limestone, clay and gypsum. the main step in the manufacture of cement is the heating of raw meal or slurru in the rotary kiln at a very high temperature 1400-1600^(@)C . Finally 2% or 3% gypsum is added. When cement is mixed with water and left as such for sometime, it becomes a hard mass. This is known as setting of cement. It is believed that varous aluminates and silicates present in the cement form hydrates with water which seperate in the form of gel. the gel formed start losing water partly by evaporation and partly by forming hydrates with unhydrated constituents. this results in the formation of a hard mass. Portland cement does not contain

Cement is one of the most important building material of the present time. It is a dirty greyish heavy powder containing calcium aluminates and silicates. The important raw materials neede for the manufacture of cement are limestone, clay and gypsum. the main step in the manufacture of cement is the heating of raw meal or slurru in the rotary kiln at a very high temperature 1400-1600^(@)C . Finally 2% or 3% gypsum is added. When cement is mixed with water and left as such for sometime, it becomes a hard mass. This is known as setting of cement. It is believed that varous aluminates and silicates present in the cement form hydrates with water which seperate in the form of gel. the gel formed start losing water partly by evaporation and partly by forming hydrates with unhydrated constituents. this results in the formation of a hard mass. Setting of cement is

Cement is one of the most important building material of the present time. It is a dirty greyish heavy powder containing calcium aluminates and silicates. The important raw materials neede for the manufacture of cement are limestone, clay and gypsum. the main step in the manufacture of cement is the heating of raw meal or slurru in the rotary kiln at a very high temperature 1400-1600^(@)C . Finally 2% or 3% gypsum is added. When cement is mixed with water and left as such for sometime, it becomes a hard mass. This is known as setting of cement. It is believed that varous aluminates and silicates present in the cement form hydrates with water which seperate in the form of gel. the gel formed start losing water partly by evaporation and partly by forming hydrates with unhydrated constituents. this results in the formation of a hard mass. Concrete is a mixture of

This law was given by, a French chemist , Joseph Proust. He stated that a given compound always contains exactly the same proportion of elements by weight. Proust worked with two samples of curpic carbonate- one of which was of natural origin and the other was synthetic one . He found that the composition of elements present in it was for both the samples as shown below: Thus, irrespective of the source, a given compound always contains same elements in the same proportion. The validity of this law has been confrmed by various experiments. It is sometimes also reffered to as Law of constant composition. Limitation: This law is not applicable if the compound is formed from different isotopes of an element . The two isotopes of carbon C-12 and C-14 form carbondioxide C^(12)O_(2) and C^(14)O_(2) . The ratio of C : O is 12 : 32 and 14 : 32 respectively .It is not a constant ratio. 6.488 g lead with 1.002 g oxygen to form an oxide. This oxide is also obtained by heating Pb(NO_(3))_(2) , It is found that % of lead in this oxide is 86.62 .Show that these date illustrate the law of definite proportions.

Choose the correct code regarding Roasting process. (I) It is the process of heating ore in air to obtain the oxide (II) It is an exothermic process (III) It is used for hydrated oxide and oxysalt ore (IV) It is used after the concentration of ore