class 10 science chapter 2 notes pdf: In which we will discuss the presentation of H⁺ and OH⁻ ions in terms of their definition, general properties, examples and uses, the concept of PH scale, the importance of PH scale in everyday life, sodium hydroxide, bleaching powder, baking soda, washing soda and plaster of Paris, etc.
class 10 science chapter 2 notes
Acid is called acid in the English language, the word acid is derived from the Latin word 'acids', which means sour. So we can say that substances that are sour in taste are acids. Physical properties of acids:-Chemical properties of acids:-
️Types of Acids:-
Those acids which completely ionize in aqueous solution are called strong acids. Examples of strong acids are sulfuric acid (H₂SO₄), hydrochloric acid (HCI), nitric acid (HNO₃), hydrobromic acid, etc. Strong acids have a high ability to give up protons i.e. hydrogen ions (H + ) i.e. strong acids dissociate into ions of their constituent elements. Acids, which are partially ionized but not completely ionized in an aqueous solution are called weak acids. Examples of weak acids are acetic acid (CH₃COQH), formic acid (HCOOH), hydrogen sulfide (H₂S), etc. Weak acids do not completely give up their hydrogen ions (H+). At the same concentration, weak acids have a higher pH than strong acids. In which acid is present in large quantities, whereas water is in small quantities. In which acid is present in small quantities, whereas water is present in large quantities. Substances whose taste is bitter and which feel like soap when touched. are called bases.️ class 10 science chapter 2 notes: Properties of base
️Indicator:-
Indicators show the presence of an acid or a base in a given solution. Their color or smell changes in acidic or basic medium.️ Types of pointer:-
Well, there are many types of detectors. But their common types are as follows:- Those indicators which are obtained from natural sources are called natural indicators. For Examples- Litmus, Red cabbage juice, Turmeric, Hydrangea flower juice, etc. ️ 2. Synthesized indicator:- These are those indicators that are not natural but are made by chemical substances. Eg:- Methyl orange and phenolphthalein etc. They are used to test for acids and bases. ️ 3. Aromatic indicator:- There are some substances whose odor changes in acidic or basic medium, such substances are called odorous indicators. Eg:- Onion and clove and oil etc. ️ 4. Universal indicator:- A universal indicator is a mixture of different chemicals that tell about a substance with different pH by changing its color whether it is a base or an acid. Metals displace hydrogen atoms from acids in the form of hydrogen gas and form a compound called salt. When a burning candle is brought near a test tube containing hydrogen gas, the sound of pop is produced. This test is used to show the presence of hydrogen. ️ The reaction of acid and base with metal:- Acid + Metal → Salt + Hydrogen 2HCl + Zn → ZnCl₂ + H₂ Alkali + Metal → Salt + Hydrogen 2NaOH + Zn → Na₂ZnO₂ + H₂ ️ Such substances which do not change the color of red or blue litmus paper are called neutral. Such substances are neither acidic nor basic. Such as - salt, salt, calcium chloride, sodium carbonate, sodium bicarbonate, etc. When the observed effect of the base by acid and effect of acid by the base is over and as a result salt and water are obtained, a neutralization reaction takes place.️ The reaction of metallic oxides with acids:-
Metallic oxide + acid → salt + water CaO + 2HCl → CaCl₂ + H₂O Metallic oxides have a basic nature. Because they react with acids to form salts and water. Example:- Cuo, Mgo All acids produce H⁺ ions. All bases produce OH⁻ ions. On adding an acid or a base to water, the concentration of the ion (H₃O⁺ or OH⁻) decreases per unit volume. This process is called dilution and acids or bases are diluted.️ Strength of base and acid:-
The strength of a base or acid depends on the number of H+ ions or OH- ions produced by it. We can determine the strength of an acid or a base by a universal indicator. There is a mixture of several indicators. These indicators show different concentrations of hydrogen ions in a solution in different colors. A scale was developed to find the concentration of H⁺ ion present in a solution called pH scale. The p in pH is 'Pusenz' (Potenz) which is a German word, which means power. If:- ️ Importance of pH in daily life:- Plants and animals are sensitive to pH. , Our body works between the 7.0 to 7.8 pH range.class 10 science chapter 2 notes pdf : Soil pH:-
Plants require a specific pH range for good yield. If the pH of the soil of a place is low or high, then farmers add acidic or alkaline substances to it as needed. Our stomach produces hydrochloric acid (HCI) which aids in the digestion of food. In the case of dyspepsia, the stomach produces acid in excess, due to which pain and burning are experienced in the abdomen. To get rid of this pain, bases like antacids are used which neutralize the excess amount of acid. eg (milk of magnesia) When the pH value of rainwater falls below 5.6, it is called acid rain.️ Chemicals from common salt:-
Sodium Chloride NaCl is called common salt which we use in food. It is made from seawater. Rock salt is a substance found in the form of brown crystals. It is obtained by extraction like coal. Common salt thus obtained contains many substances of our daily use; Eg :- Sodium hydroxide is an important raw material for baking soda, washing soda, bleaching powder, etc. On passing electricity through an aqueous solution of sodium chloride (salt water), it dissociates to form sodium hydroxide. This process is called Chlor-alkali process because the products produced are chlorine (chlor) and sodium hydroxide (alkali). 2NaCl (aq) + 2H₂O(l) → 2NaOH (aq) + Cl₂(g) + H₂( g ) Chlorine gas is liberated at the anode and hydrogen gas is liberated at the cathode. Sodium hydroxide solution is also formed at the cathode. All the three products produced by this process are useful. Bleaching powder is formed by the action of chlorine on dry slaked lime [Ca(OH)₂]. Ca(OH)₂ + Cl₂ → CaOCI₂ + H2O Baking soda is commonly used in the kitchen to make delicious crispy pakodas etc. Sometimes it is also used for quick cooking of food. The chemical name of this compound is sodium hydrogen carbonate (NaHCO₃). Sodium chloride is used as a basic substance in its preparation. ️ 4. Washing soda ( Na₂CO310H₂O ) :- Re-crystallization of sodium carbonate gives washing soda. It is a basic salt. Na₂Co₃ + 10H₂0 → Na₂CO₃ 10H₂0️ 5. Plaster of Paris CaSO₄1/2H₂0 :-
When gypsum is heated to 373K, it gives up water molecules to form calcium sulfate hemihydrate (POP). It is a white powder, which when mixed with water, it again becomes gypsum and provides solid. USE of plaster of Paris class 10 -the water of crystallization class 10
The number of water molecules in a formula unit of salt is called water of crystallization. Example:-Here we add all topics related to class 10 science chapter 2 notes and all formulas like (the plaster of Paris formula ) and many more.
