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(a) dilutesulphuric acid reacts with zinc granules.
(b) dilute hydrochloric acid reacts with magnesium ribbon.
(c) dilutesulphuric acid reacts with aluminium powder.
(d) dilute hydrochloric acid reacts with iron fillings.
(a) Acid have a --------tasks and they turn -------litmus to --------
(b) Substance do not show their acidic properties without ----------
(c) Acids produce ------- ions on dissolving in water.
(d) Those substance whose smell (or odour) changes in acidic or basic solutions are called ------indicators.
(e) Onion and vanilla extract are ------ indicators.
(a) What are X, Y and Z?
(b) Write equations for the reactions which take place:
(i) when limestone reacts with dilute HCl
(ii) when gas X reacts with lime water to form white precipitate Y
(iii) when excess of gas X dissolves white precipitate Y to form a soluble compound Z
(a) Predict the new compound formed which imparts a blue-green colour to solution.
(b) Write a balanced chemical equation of the reaction which takes place.
(c) On the basis of the above reaction, what can you say about the nature of copper oxide?
(a) Name the natural indicator present in curry stain.
(b) Explain the changes in colour of this indicator which take place during washing and rinsing the shirt.
(c) What is the nature of soap (acidic/basic) as shown by the indicator present in curry stain?
(a) Acids have a pH.................than 7.
(b) Alkalis have a pH.............. than 7.
(c) Neutral substances have a pH of ...............
(d) The more acidic a solution, the ................... the pH.
(e) The more alkaline a solution, the.................... the pH.
Metal polish : Dark blue
Washing-up liquid : Yellow
Milk of magnesia : Light blue
Oven cleaner : Purple
Car battery acid : Pink
Arrange the solutions in order of their increasing pH values (starting with the one with the lowest pH).
(a) What will be the action of solution A on litmus?
(b) What will be action of solution B on litmus?
(c) Name any two substances which can give solutions like A.
(d) Name any two substances which can give solutions like B.
(e) What sort of reaction takes place when solution A reacts with solution B?
(a) What would the students have used to measure the pH?
(b) Which solution is the most acidic?
(c) Which solution is the most alkaline?
(d) Which solutions are neutral?
(e) Which solution can be used to treat wasp stings?
(f) Which solution can be used to treat bee stings?
(a) Name X and Y
(b) Write the chemical equation of the reaction of metal X with
(i) hydrochloric acid, and
(ii) sodium hydroxide solution.
Fill in the following blanks:
(a) Common salt is obtained from sea-water by the process of ...............:
(b) Rock salt is mined just like. ......................
(c) Chemical formula of washing soda is................
(d) Sodium hydrogen carbonate is.................soda whereas sodium carbonate is.......soda.
(e) The chemical formula of plaster of Paris is..............
Consider the following substances:
NaCI, Ca(OH)2, NaHCO3, NH3, Na2CO3, H2O, Cl2, CO2, CaSO4.2H2O, 2CaSO4.H2O, 2CaSO4.2H2O, CaOCI2
(a) Which two substances combine to form bleaching powder?
(b) Which four substances are utilized in the production of washing soda? (c)Which compound represents plaster of Paris?
(d) Which compound is a part of baking powder?
(e) Which compound is used as an antacid?