ACIDS, BASES & SALTS.docx

ACIDS, BASES & SALTS WORK-SHEET CLASS-7th 1\. State whether the following statements are true or false. Correct the false statements. \(a) All substances are either acidic or basic. \(b) A compound if acidic will turn all indicators red. \(c) Lime water turns red limus blue. \(d) Common salt...

ACIDS, BASES & SALTS WORK-SHEET CLASS-7th 1\. State whether the following statements are true or false. Correct the false statements. \(a) All substances are either acidic or basic. \(b) A compound if acidic will turn all indicators red. \(c) Lime water turns red limus blue. \(d) Common salt dissolved in water turns blue litmus red. \(e) Phenolphthalein is a natural indicator. \(f) Calamine can be used to treat ant's sting. \(g) Lemon water is basic in nature. 2\.  Paheli is suffering from indigestion due to acidity. Is it advisable to give her orange juice in this situation and why? 3\.   Form a sentence using the following words-baking soda, ant bite, moist, effect, neutralised, rubbing. 4\.  Match the substances in Column I with those in Column II. Column 1 Column II ---------- ------------------- ------- ---------------- (a) Tartaric acid (i) soap (b) Calcium hydroxide (ii) curd (c) Formic acid (iii) unripe mangoes (d) Sodium hydroxide (iv) ant's sting (e) Lactic acid (v) lime water 5\. Fill in the blanks in the following sentences. \(a) Lemon juice and vinegar taste \_\_\_\_\_ because they contain \_\_\_\_\_. \(b) Turmeric and litmus are \_\_\_\_\_ acid-base indicators. \(c) Phenolphthalein gives \_\_\_\_\_ colour with lime water. \(d) When an acidic solution is mixed with a basic solution, they \_\_\_\_\_ each other forming \_\_\_\_\_ and water. 6\.  A farmer was unhappy because of his low crop yield. He discussed the problem with an agricultural scientist and realised that the soil of his field was either too acidic or too basic. What remedy would you suggest the farmer to neutralise the soil? 7\. You are provided with four test tubes containing sugar solution, baking soda solution, tamarind solution, salt solution. Write down an activity to find the nature (acidic/basic/ neutral) of each solution. 8\. Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village is flowing into the pond which probably caused the fish to die. \(a) Explain why the fish were dying. \(b) If the factory waste is acidic in nature, how can it be neutralised? 9\. Explain two neutralisation reactions related to daily life situation. 10\. What is the use of litmus paper? What is the natural colour of litmus paper? 11\.  Why is toothpaste alkaline? 12.Define indicator. Give two examples of natural & synthetic indicators each. 13\. Define neutrilisation reaction with the help of an example. 14\. State atleast four differences between acids ans bases. 15\. Blue litmus paper is dipped in areated soft drink. What will happen?What is the nayure of the solution?