Dhoran 7 Samajik Vigyan Paper Solution 2022 || Varshik Pariksha 2022

Separate the following into substances having pH values above and below 7. How do these influence litmus paper? (i) Lemon juice (ii) Solution of washing soda (iii) toothpaste (iv). Vinegar (v). Stomach juices.

(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.

The average of 7 consecutive numbers is 20 . The largest of these numbers is (a) 2022quad (c)23quad (d)24

You have four solutions A, B, C and D. The pH of solution A is 6, B is 9, C is 12 and D is 7. (a) Identify the most acidic and most basic solutions. (b) Arrange the above four solutions in the increasing order of H^+ ion concentration. (c) State the change in colour of pH paper on dipping in solution C and D.

(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 mixture of three gases A,B and C is passed first into acidified K_(2)Cr_(2)O_(7) solution when A is absorbed turning the solution green. The remainder of the gas is passed through excess of lime water which truns milky resulting in the absorption of B. The residual gas C is absorbed by alkaline pyrogallol solution. However the original mixture does not run lead acetate paper black. Identify A,B, & C ( Give necessary equations ).

(a) How is pH paper used to find the pH of a solutions? (b) The pH value of water is 7. What will be the pH value of (i) aqueous solution of sodium hydroxide and (ii) dil HCl.