Sunday, 7 July 2019

10th Class Chemistry Notes Chapter 2 Acids, Bases and Salts

10th Class Chemistry Notes Chapter 2
If you are in search of the notes of chemistry chapter 2 Acids, Bases and Salts of class 10th then you are at right page because here we have shared 10th Class Chemistry Notes Chapter 2 Acids, Bases and Salts pdf download or read online.

Q.1 What is meant by Acid?
 Ans. The acid is derived from the Latin word "Acidius" meaning sour. Acid is a substance which has sour taste and turns blue litmus red.
 Q.2 Write down characteristic properties of Acids and bases Ans. Properties of acids and bases
Q.3 Define Arrhenius acid. Give example?
 Ans. According to Arrhenius concept acid is a substance which dissociates in aqueous solution to give hydrogen ions. For example HCI is an acid because it ionizes in aqueous solution to provide H'ions.
 Q4 Define Arrhenius base. Give example
 Ans. According to Arrhenius concept base is a substance which dissociates is aqueous solution to give hydroxide ions. For example the substance NaOH is a base because it ionizes in aqueous solution to provide OH ions.
 Q.5 Define Bronsted and Lowry acid.
 Ans. An acid is a substance (molecule or ion) that can donate a proton (H) to another substance. e.g HCI and CH COOH
 Q.6 Define Bronsted Lowry base.
 Ans. A base is a substance that can accept a proton (H) from another substance. e.g H2O and NHQ.7 Define conjugate acid and base.
 Ans. Conjugate acid
 A conjugate acid is a specie formed by accepting a proton by a base. e.g., H,O Conjugate base
 A conjugate base is a specie formed by donating a proton by an acid. e.g.. CI Q.8 Define amphoteric.
 Ans. A substance that can behave as an acid as well as a base is called amphoteric. For example water is an amphoteric compound
 Q.9 Write down limitations of Bronsted Lowry concept.
 Ans. It has been observed that there are certain substances which behave as acids though they do not have the ability to donate a proton e.g SO3. Similarly CaO behaves as a base butit cannot accept a proton. These observations prove the limitations of Bronsted Lowry concept of acids and bases.
 Q.10 Define Lewis-base. Give example.
 Ans. A base is substance (molecule or ion) which can donate a pair of electrons. e.g NH3.
 Q.11 Define Lewis acids. Give example.
 Ans. An acid is a substance (molecule or ion) which can accept a pair of electrons. e.g AICls and BF
 Q.12 Define Adduct
 Ans. The product of any Lewis acid-base reaction is a single specie called an adduct
Q.13 Write down the names of three mineral acids.
 Ans. Following acids are called mineral acids. Hydrochloric acid (HCI) Sulphuric acid (H2SO4) and nitric acid (HNO.).
Q.14 Write down uses of sulphuric acid.
 Ans. It is used to manufacture fertilizers, ammonium sulphate, calcium super phosphate, explosives, paints, dyes and drugs. It is also used as an electrolyte in lead storage batteries.
 Q.15 Write down uses of nitric acid.
 Ans. It is used in manufacturing of fertilizer (ammonium nitrate), explosives, paints, drugs and etching designs on copper plates
 Q.16 Write down uses of hydrochloric acid.
 Ans. It is used for cleaning metals, tanning and in printing industries.
 Q.17 Write down uses of benzoic acid.
 Ans. It is used for food preservation
Q.18 Write down uses of sodium hydroxide.
 Ans. It is used for manufacturing of soap, artificial silk, as laboratory reagent in textile and paper industries.
 Q.19 Write down uses of calcium hydroxide.
 Ans. It is used for manufacturing of bleaching powder, softening of hard water and neutralizing acidic soil and lakes due to acid rain.
 Q.20 Write down uses of potassium hydroxide.
 Ans. It is used in alkaline batteries.
Q.21 Write down uses of magnesium hydroxide.
 Ans. It is use as a base 10 neutralize acidity in the stomach. It is also used for treatment of bees stings.
 Q.22 Write down uses of Aluminium hydroxide.
 Ans. It is used as foaming agent in fire extinguishers
Q.23 Write down uses of ammonium hydroxide.
 Ans. It is used to remove grease stains from clothes.
Q.24 Define pH. Write down its formula.
 Ans. pH is the negative logarithm of molar concentration of the hydrogen ions pH -log [H
 Q.25 Write down uses of pH
 Ans. i) It is used to determine acidic or basic nature of a solution ) It is used to produce medicines, culture at a microbiological particular concentration of H ion.
 ii) It is used to prepare solutions of required concentrations necessary for certain biological reactions
 Q.26 What are indicators. Give example?
 Ans. Indicators are the organic compounds. They have different colours in acidic and alkaline solutions. Litmus is a common indicator. It is red in acid and blue in alkaline solutions.
 Q.27 What are universal indicators?
 Ans. Some indicators are used as mixture. The mixture indicators give different colours at different pH values. Hence it is used to measure the pH of a solution. Such a mixed indicator is called universal indicator.
Q.28 Who are analytical chemists?
 Ans. Analytical chemists examine substances qualitatively and quantitatively. They indentify substances and evaluate their properties.
 Q.29 Define salts.
 Ans. Salts are inorganic compounds generally formed by neutralization of an acid with a base. e.g., sodium chloride (NaCl)
Q.30 What is acid and basic radical?
 Ans. Salts are made up of positive ions (cations) and negative ions (Anions). A cation is metallic and derived from a base therefore it is called basic radical. While anion is derived form acids therefore it is called acid radical.
 Q.31 Write down any two characteristics of salts.
 Ans. salts are ionic compounds found in crystalline form. They have high melting and boiling points.
 Q32 Define normal or neutral salts.
 Ans. A salt formed by the total replacement of ionizable H ions of an acid by a positive metal ion or NH ions is called normal or neutral salt. e.g NaCl
Q.33 Define Acidic salt.
 Ans. These salts are formed by partial replacement of H ions of an acid by a positive metal ion. e.g KHSO
 Q.34 Define basic salt.
 Ans. Basic salts are formed by the incomplete neutralization of a polyhydroxy base by an acid. e.g Al(OH)2 CI
 Q.35 Define double salt. Give example.
 Ans. Double salts are formed by two normal salts when they are crystallized from a mixture of equimolar saturated solutions. The individual salt components retain their properties. For example Mohr's salt FeSO4. (NH4)2 SO4, 6H20.
 Q.36 Define Mixed salt. Give example.
 Ans. Mixed salts contain more than one basic or acid radicals. Bleaching powder Ca(OCI) Cl, is an example of mixed salts.
Q.37
b) pH values less than 7 1) vinegar
 2) Citrus fruits
 3) Butter
 c) pH values equal to 7
 1) Water
 2) NaCl
 3) Sugar
 Q.40 Define a base and explain all alkalis are bases, but all bases are not alkalis.
 Ans. A base is a substance which turn red litmus to blue and having pH value greater than 7.
 Water soluble base is called alkali but some bases are not soluble in water, so all alkalis are bases but all bases are not alkalis.
 Q.41 Define Bronsted-Lowry base and explain with an example that water is Bronsted-lowry base.And. Bronsted-Lowry base is a substance(molecule or ion) which can accept a proton (H) from another substance. For example, when HCL dissolves in water, HCl acts, as an acid and HO act as a base because it accepts a proton.
 HC+HO = H,0* +CI
 Acid base
 Q.42 How can you justify that Bronsted-Lowry concept of acid and base is applicable to non aqueous solutions?
 Ans. According to Bronsted-Lowry concept:
 An acid is a compound which donates a proton (H)."
 "A base is a compound which accepts a proton (H)."
 So, the compounds which have H ions also act as acids in addition to water e.g.. CH COOH while the compounds which have not OH ions also act as base c.g., NH
Q.43 Which kind a bond forms between Lewis acid and base?
 Ans. Coordinate covalent bond forms between Lewis acid and base.
 Q.44 Why H' ion acts as a Lewis acid?
 Ans. Because it has an empty orbital that can accommodate a pair of electrons.
Q.45 Name two acids used in the manufacture of fertilizers.
 Ans. Sulphuric acid and nitric acid both are used in the manufacture of fertilizers0.46 Define pH. What is the pH of pure water?
 Ans. pH is the negative logarithm of molar concentration of the hydrogen ions, that is pH log H The pH value of pure water is 7
 Q.47 How many times a solution of pH I will be stronger than that of a solution having pH 2?
 Ans. Because the pH scale is logarithmic, a solution of pH has 10 times higher concentration of [H] than that of a solution of pH2
Q.48 Na SO is a neutral salt while Nalls, is an acidic salt justify.
 Ans. Because in Na SO, there is total replacement of ionizable H ions. While in NaHSO the partial replacement of a replaceable H" ions of an acid takes place by a positive metal ion. It turns red litmus to blue
Q.49 Give few characteristics of salts.
 Ans. There are following characteristics of salt
 )Salts are ionic compounds found in crystalline form.
 2) They have high melting and boiling point.
Q.50 How the soluble salts are recovered from water?
 3) Ans. Soluble salts are recovered by evaporation or crystallization.
Q.51 How the insoluble salts are prepared?
 4) Ans. In this method, usually solutions of soluble salts are mixed. During the reaction 5) exchange of ionic radicals(i-e metallic radicals exchange with acidic radicals) takes place to 6) produce two new salts. One of the salt is insoluble and other is soluble. The insoluble salt 7) precipitates(solidify in solution) c.g.
 AGNO +NaCL AgCl NaNO
 Na,COCuSO CuCo Na SO
 Q.52 Why a salt is neutral, explain with an example?
 Ans. A salt is formed by the total replacement of ionizable H ions of an acid by a positive metal ion or NH ions is called normal or neutral salt. These salts are neutral to litmus.
 HCL... KOH - >KCL. + H2O
Q.53 Name an acid used in the preservation of food.
 Ans. Benzoic acid is used for food preservation.Q54 Name the acids present in.
 Ans.
 1) Vinegar:
 Acetic acid
 2) Ant sting
 Formic acid
 3) Citrus fruit
 Citric acid
 4) Sour milk
 Lactic acid
 Q.55 How can you justify that Pb(OH)NO is a basic salt?
 Ans. Pb(OH) NOis a basic salt because it is formed by the incomplete neutralization of a poly hydroxyl base by an acid.
 = Pb(OH)3+HNO; Pb(OH)NO:+H2O
 It can react with acids to form normal salts. Pb(OH)NO, + HNO Pb(NO) +H O Q.56 You are in a need of an acidic salt. How can you prepare it?
 Ans. An acidic salt is formed by the partial replacement of a replaceable H ions of an acid by a positive metal ion.

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