Dhoran 10 Samajik Vigyan Ekam Kasoti December 2021 Paper Solution

(a). What effect does the concentration of H^(+) (aq) ions have on the nature of a solution? (b). What effect does the concentration of OH^(-) ions have on the nature of a solution? (c). Someone put some universal indicator paper into vinegar. The pH is 3. What does this tell you about the vinegar? (d). Someone put some universal indicator paper onto wet soap. the pH is 8. What does this tell you about the soap? (e). State whether a solution is acidic, alkali or neutral if its pH is: (i) 9 (ii) 4 (iii) 7 (iv) 1 (v) 10 (vi) 3.

A sweet smelling liquid A has molecular formula C_5 H_(10) O_2 A does not change colour of moistened litmus paper but on acid hyrolysis produces two fragments B and C. B gives effervescence with aqueous NaHCO_3 but 'C' does not 'C' on treatment with PCl_5 gives an alkyl chloride 'D' 'D' on dissolving in Etheral solution of Mg and passing CO_2 through this solution and finally acidifying product with HCl gave B. Identify A to D.

(i) Four samples A, B, C and D change the colour of pH paper or solution to Green, Reddish-pink, Blue and Orange. Their pH was recorded as 7, 2, 10.5 & 6 respectively. Which of the samples has the highest amount of Hydrogen ion concentration? Arrange the four samples in the decreasing order of their pH. (ii) Rahul found that the Plaster of Paris, which he stored in a container, has become very hard and lost its binding nature. What is the reason for this? Also, write a chemical equation to represent the reaction taking place (iii) Give any one use of Plaster of Paris other than for plastering or smoothening of walls.

Amongst the following, the total number of compounds whose equesous solution turns red litmus paper blue is: {:(NaCN,KCl,CH_(3)COONH_(4),NaH_(2)PO_(4),ZnCl_(2), Na_(3)PO_(4)),(Fe(NO_(3))_(3),Na_(2)CO_(3),NH_(4)Cl,NaHCO_(3),Na_(2)C_(2)O_(4),Na_(2)HPO_(4)):} Given: {:("Acid",ka_(1),ka_(2),ka_(3)),(H_(3)PO_(4),10^(-3),10^(-8),10^(-12)),(H_(2)CO_(3),10^(-6),10^(-11),-),(H_(2)CO_(3),10^(-2),10^(-5),-):}