Classify the following substancesd into 2 groups :
` PH gt 7 and pH gt 7`
Lemon juice Wine Limewater Blood Acid rain How do these substances react with litmus paper ?

Which of the following when mixed, will given a solution with pH gt 7 .

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.

Which buffer solution out of the following will have pH gt 7 ?

Give reasons for the following : (i) Distilled water does not conduct electricity but rain water does. (ii) Acids do not show acidic behaviour in the absence of water. (iii) A solution with pH less than 7 is acidic. (iv) HCI shows acidic behaviour in aqeous solution but C_(2)H_(5)OH does not .

Study the following statements regarding acid rain and select the incorrect ones. (i) Acid rain refers to the rainfall and other forms of precipitation with a pH of less than 5. (ii) Oxides of sulphur and nitrogen are released from automobile exhausts, industries , power plants, etc. (iii) These oxides of sulphur and nitrogen, may react with water in the air and form sulphuric acid (H_(2)SO_(4)) and nitric acid (HNO_(3)) . (iv) Acid rain has harmful effects on animals and human beings but no characteristic impact on plants.

pH calculation upon dilute of strong acid solution is generally done by equating n_(H) in original solution & diluted solution.However . If strong acid solution is very dilute then H^(+) from water are also to be considered take log3.7=0.568 and answer the following questions. A 1 litre solution of pH=6 (solution of a strong acid) is added to the 7//3 litres of water.What is the pH of resulting solution? Neglect the common ion effect on H_(2)O .

The dissociation of weak electrolyte (a weak base or weak acid) is expressed in terms of Ostwald's dilution law. An acid is substance which furnishes a proton or accepts an electron pair, where a base is proton acceptor or electron pair donor. Stronger is acid, weaker is its conjugate base. The dissociation constants of an acid (K_(a)) and its conjugate base (K_(b)) are related by K_(w)=K_(a)xxK_(b) , where K_(w) is ionic product of water equal to 10^(-14) at 25^(@)C . The numerical value of K_(w) however increase with temperature. In a solution of an acid or base [H^(+)][OH^(-)]=10^(-14) . Thus the [H^(+)] in a solution is expressed as: [H^(+)]=10^(-pH) and pH+pOH=14 . Buffer solution are the solutions which do not show appreciable change in the pH on addition of small amount of acid or base. Which of the following statements are wrong ? (1) Increase in temperature has no effect on neutral nature of water. (2) Increase in temperature of pure water decreases its pH. (3) Increase in temperature of pure water decreases its autoprolysis. (4) Increase in temperature of pure increase its ionic product. (5) Increase in temperature of pure water decreaseas degree of dissociation of water.