Q11 Name the acids present in the following foodstuffs which attribute to a sour taste to them- (a) Lemon juice (b)Vinegar (c) Vitamin C tablet (d)Tamarind (e) Sour milk
Q12 What does pH stand for? What does pH scale indicate?
Q13 Sweet tooth may lead to tooth decay. Explain, why? What is the role of tooth paste in preventing cavities
Q14 Write the names of five hydrated salts with their colours and formulae.
Q15 How are bases different from alkalis? Are all bases alkalies
Q16 What are strong acids and weak acids? Give two examples.
Q17 How will you test a gas which is liberated when hydrochloric acid reacts with an active metal?
Q18 Indicate with the help of a diagram the variation of pH with change in concentration of hydrogen ion and hydroxide ions showing Increase of acidic and basic nature. (i) Increase and decrease of H ion
Q19 What are indicators ? Give examples and their colour changes in different medium.
Q20 How will you prepare 100 times dilute solution from 1mL of concentrated sulphuric acid solution ? What precaution would you suggest and why?
Answers & Comments
Answer:
(a) citric acid
(b) acetic acid
(c) citric acid
(d) tartaric acid
(e) lactic acid
12.a measurement of the level of acid or alkali in a substance. pH is a measure of how acidic/basic water is.
13.Remains of the sweets being taken may be present in between the teeth and bacteria acts on them at night producing an acid that causes decay of the enamel of the teeth. Toothpaste contains fluorides which is the best way to help prevent tooth decay
14.CuSO4.5H2O Copper sulphate pentahydrate Blue
2.ZnSO4.7H2O Zinc sulphate heptahydrate White
3.CoCl2.6H2O Cobalt chloride hexahydrate Pink
4.CrCl3.6H2O Chromium chloride hexahydrate
Dark green
sorry but i know only 4 names
15.Alkali compounds are types of bases that dissolve in water whereas the base neutralizes the acid. Not all bases are alkali
16.The acid that ionizes completely in solution is called strong acids.
Example of a strong acid is HCl.
The acid which does not dissociate completely in water solutions is called as a weak acid.
Example for weak acid is acetic acid(CH3COOH).
17.Hydrogen gas is liberated when an active metal reacts with hydrochloric acid. For testing the presence of hydrogen gas, bring a burning candle near the mouth of the test tube in which the reaction is taking place. If the gas burns with a popping sound, then it can be concluded that it is hydrogen
18.
Verified answer
Answer:
are jaldi number do na kyon Nahin de rahe jaldi do na Kuchh Nahin Karunga abhi aapko call Nahin karungi okay jaldi do