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Calcium sulphate hemihydrate is known as:
PLASTER OF PARIS is a white or yellowish, finely divided, odorless powder consisting mostly or entirely of calcium sulfate hemihydrate, CaSO4.1/2H2O.
A colourless and odourless gas is liberated when hydrochloric acid is added to a solution of washing soda. The name of the gas is:
Washing soda is chemically sodium carbonate, which is a basic salt. When dilute HCl is added to washing soda, acid base neutralisation reaction takes place and sodium chloride is formed along with water and carbon dioxide. Following is the chemical equation for the reaction
Na2CO3 + 2HCl → 2NaCl + H2O + CO2
Hence, the correct answer is (b) carbon dioxide.
Baking powder is a mixture of:
Baking powder is a mixture of baking soda NaHCO3,(sodium hydrogen carbonate)and a mild edible acid such as tartaric acid
Which gas causes the bread or cake to rise making them soft and spongy?
Carbon dioxide is released when baking soda is added to cake and this makes the cake to rise making them soft and spongy.
Which of the following salt is basic in nature?
Sodium acetate (CH3COONa) is a salt in solid state and can't be regarded as an acid or base in anhydrous or molten form.
Although, being an ionic compound, sodium acetate dissociates in water to produce sodium ion Na+ and acetate ion CH3COO-. These ions react with water producing NaOH and CH3COOH.
Now, as NaOH is a strong base and CH3COOH is a weak acid, the resultant solution is basic in nature.
Hence, sodium acetate is basic in aqueous medium.
Which of the following substances is used for supporting fractured bones?
Plaster of Paris i.e, CaSO4.1/2H2O is used by doctors as plaster for supporting fractured bones in the right position.
Which of the following is widely used in the oxy-acetylene welding and cutting metals?
The oxy-acetylene flame refers to a gas torch that burns a mixture of acetylene and oxygen to produce a high-temperature flame. Therefore, ethyne, i.e. acetylene is used for the production of oxy-acetylene flame for welding and cutting metals.
The compounds obtained on heating baking soda are:
Sodium hydrogen carbonate (also known as sodium bicarbonate or bicarbonate of soda) has the chemical formula NaHCO3 . When it is heated above about 80°C it begins to break down, forming sodium carbonate, water and carbon dioxide.
Plaster of Paris is prepared by heating which of the following compounds?
Gypsum is calcium sulphate dihydrate. The chemical formula of gypsum is CaSO4·2H2O
Plaster of paris is prepared by heating gypsum to a temperature of 373K.When gypsum is heated to a temperature of 373k ,It loses three-Fourths of its water of crystallisation and forms plaster of paris.
What is used as an antacid?
The excess of acid in the stomach causes acidity. As NaHCO3 is alkaline in nature, it neutralizes the excess acid and relieves discomfort. Hence it is an essential ingredient in antacids. Following equation explains its reaction with HCl
NaHCO3 + HCl → NaCl + H2O + CO2↑