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Which one of the following has a higher concentration of H+ ions? 1M HCl or 1M CH3COOH?
Why CH3COOH is considered a weak acid whereas HCl is considered as a strong acid?
Which gas is evolved when dil. HCl reacts with metal bicarbonate? How is it recognized?
What effect does an increase in concentration of H+ (aq) ions in a solution have on the pH of a solution?
Name the gas evolved when dil. HCl reacts with an active metal. How is it recognized?
Why does tooth decay start when the pH of mouth is lower than 5.5?
How is the pH of a solution of an acid influenced when it is diluted?
Fresh milk has a pH of 6. When it changes into curd (yoghurt), will its pH value increases or decreases? Why?
Arrange the pH values of 0, 2, 4 and 6 in the increasing value of H+ (aq) ions conc.?
Why the flow of acid rainwater into a river make the survival of aquatic life in the river difficult?
Crystals of CuSO4 are heated in a test tube for some time.
(a) What is the colour of CuSO4 crystals:
(i) before heating, and
(ii)after heating?
(b) What is the source of liquid droplets seen on the inner upper side of the test tube during the heating process?
(i) Name the products formed when NaHCO3 is heated.
(ii) Write the chemical equation for the reaction involved in the above.
Write the name and chemical formula of the calcium compound used for disinfecting drinking water. How is this compound manufactured?
Show the decomposition of gypsum to P.O.P. and back interconversion of P.O.P. of gypsum.
What happens when:
(a) CO2 is passed through lime water in a limited quantity?
(b) CO2 is passed through lime water in excess?
Give a reason to explain why:
(a) bleaching powder smell strongly of chlorine?
(b) bleaching powder does not dissolve completely in water?
What is the chemical formula for washing soda? How can it be obtained from baking soda? Describe two applications of washing soda.
What is the difference between litmus solution indicator and universal indicator solution? How synthetic indicators differ from natural indicators?
(a) zinc reacts with NaOH
(b) zinc reacts with HCl?
Give two characteristics each of acids and bases.
Explain chlor-alkali process. Why is it called so?
Give reason why:
(a) water should not be added to concentrated acid?
(b) antacids are required when there is pain or irritation in the stomach?
(c) Baking soda should be rubbed on bee-stung area?
What is meant by water of crystallisation? Name four such salts which contain water of crystallisation in them. Why P.O.P. is written as CaSO4.1/2H2O?
Why NaHCO3 is used in soda-acid fire extinguisher as well as for making baking powder.
(a) tartaric acid is added while making banking powder?
(b) bleaching powder is used for disinfecting drinking water?
(c) strong acid and concentrated acid do not mean the same thing?
With the increase in the concentration of hydrogen ions, the pH value will:
The colour of pH paper strip at the pH valued of 1, 7, and 14 will be:
Which of the following is a strong acid?
Which of the following is a weak acid?
Which of the following is a mineral acid?
Which of the following contains oxalic acid?
The compound which is used in glass, soap and paper industries is:
The formula of Gypsum and Plaster of Paris is:
The compound which is used as an oxidizing agent in many chemical industries is:
The compound which is used for removing permanent hardness of water is:
Common salt besides being used in kitchen can also be used as the raw material for making:
(i) washing soda
(ii) bleaching powder
(iii) baking soda
(iv) slaked lime
Which of the following are present in a dilute aqueous solution of hydrochloric acid?
Which of the following statements is correct about an aqueous solution of an acid and of a base?
(i) Higher the pH, stronger the acid
(ii) Higher the pH, weaker the acid
(iii) Lower the pH, stronger the base
(iv) Lower the pH, weaker the base
Sodium carbonate is a basic salt because it is a salt of:
Calcium phosphate is present in tooth enamel. Its nature is:
A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?
Which of the following gives the correct increasing order to acidic strength?
What happens when a solution of an acid is mixed with a solution of a base in a test tube?
(i) The temperature of the solution increases
(ii) The temperature of the solution decreases
(iii) The temperature of the solution remains the same
(iv) Salt formation takes place
Write true or false for the following statements:
The separation of H+ ion from HCl molecules can occur in the absence of water.
Acids give H3O+ or H+(aq) ion in water.
The process of dissolving an acid or a base in water is highly exothermic one.
Care must be taken while mixing concentrated nitric acid or sulphuric acid with water. The water must always be added slowly to the acid with constant stirring.
Mixing an acid or base with water results in increase in the concentration of ions (H3O+/OH–) per unit volume.
The universal indicator shows same colour at different concentrations of hydrogen ions in a solution.
On the pH scale, we can measure pH from 0 (very acidic) to 14 (very alkaline).
Higher is the hydronium ion concentration, higher is the pH value.
Acids that give rise to more H+ ions are said to be strong acids, and acids that give less H+ ions are said to be weak acids.
When the pH of rainwater is more than 5.6, it is called acid rain.
