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Select the appropriate answer for the given question:
Answer variants:
(a) Because it is basic in nature, 'B' with pH \(3\) will turn blue litmus red.
(b) Because 'A' is acidic in nature, it will turn phenolphthalein from colourless to pink with a pH of \(10.5\).
(b) Because 'A' is acidic in nature, it will turn phenolphthalein from colourless to pink with a pH of \(10.5\).
Plaster of Paris or calcium sulphate hemihydrate is a white compound that hardens when mixed with the appropriate amount of water.
When gypsum is heated in a rotating kiln at \(373 K\) it loses all its water molecule and forms calcium sulphate hydrate\((CaSO_4)_2.H_2O\).
\(2CaSO_4.2H_2O \xrightarrow {373K}(CaSO_4)_2.H_2O + 3H_2O\)
When water is added to plaster of paris it gives gypsum.
\(CaSO_4.\frac{1}{2}H_{2}O + 1\frac{1}{2}.H_{2}O\rightarrow CaSO_4.2H_2O\)
When gypsum is heated in a rotating kiln at \(373 K\) it loses all its water molecule and forms calcium sulphate hydrate\((CaSO_4)_2.H_2O\).
\(2CaSO_4.2H_2O \xrightarrow {373K}(CaSO_4)_2.H_2O + 3H_2O\)
When water is added to plaster of paris it gives gypsum.
\(CaSO_4.\frac{1}{2}H_{2}O + 1\frac{1}{2}.H_{2}O\rightarrow CaSO_4.2H_2O\)
(a) Dry ammonia gas has no effect or changes with litmus paper as there is no dissociation of ions takes place.
(b) Ammonia in the presence of water, red litmus paper is turned blue*em*. This is because the ions dissociate in an aqueous solution.
(b) Ammonia in the presence of water, red litmus paper is turned blue*em*. This is because the ions dissociate in an aqueous solution.
1. What is the action of litmus on dry ammonia gas and solution of ammonia gas in water?
2. A white chemical compound becomes hard on mixing proper quantity of water. It is also used to maintain joints in fixed position. Name the chemical compound and write its chemical formula. Write the chemical equation to show what happens when water is added to this compound in proper quantity.
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