17. Why metallic oxides are called basic oxides and non-metallic oxide are called acidic oxides?
18. What is pH scale? What is pH value of salt formed by a
(a) weak acid and strong base ?
(b) strong acid and strong base ?
Q.19 A metal compound 'A' reacts with dil H.So, to produce a gas which
extinguisher a burning candle. Identify compound 'A' and gas produces .Write a balanced chemical equation for the reaction if one of compound
formed is sodium sulphate .
Q.20 The pH of salt used to make tasty and crispy pakoras is 14. Identify and write the chemical equation for its formation list its two uses.
(CBSE-2018)
Q.21 A compound which is prepared by gypsum has the property of hardening when mixed with water identify and write its chemical formulae. Write the chemical equation for preperation and mention any
one use of it? (CBSE sample paper-2018)
Q.22 Identify the acid and base which form sodium hydrogen carbonate.
Write the chemical equation in support of your answer state whether the compound is acidic, basicor neutral. Also write the pH. (CBSE-2019)
Q.23 A compound X on heating with excess of conc H.SO, also react with Na
metal to give colourles gas 'z' Identify 'X y' and 'z' and also write the chemical equation for formation of 'y' and also write the role of conc H.SO, in the
reaction (CBSE-2018)
Answers
Answer:
22]Let us consider a strong base 'Sodium Hydroxide' and weak acid 'Hydrogen Carbonate' to react. After the reaction, the resultant compound is Sodium Bicarbonate and water. The product is known as Baking soda which is used in cooking and is basic in nature because it weakly ionizes in water.
21]It's formula is CaSO4. 2H2O , its chemical name is calcium sulphate hemihydrate.
20]The correct answer is Sodium Bicarbonate that is obtained from sodium hydroxide with a base of 14. The chemical formula is NaHCO3.
19]When calcium carbonate reacts with hydrochloric acid, it produces carbon dioxide gas with effervescence. Carbon dioxide used as fire extinguisher. Hence, it extinguishes a burning candle. Therefore, the metal compound A is calcium carbonate.
17]Metallic oxides are basic in nature because they react with dilute acids to form salt and water. ... On the other hand, non metal oxides react with water to form acidic solutions which liberate H+ ions in solution. Therefore non metallic oxides are acidic in nature. Mark me Brainliest
Answer:
17.If you study the periodic table closely, you will find that in general, metallic oxides either dissolve in water to form basic hydroxides or react with acids to form a salt and water, which is obviously a primary property of bases. So in general, they are called basic oxides.
The non-metallic oxides react with bases to form salt and water mostly, which indicates their acidic property. So we call them ‘acidic oxides’.
There are a few exeptions among metallic oxides, too. For some metals like aluminium, the oxides are amphoteric, i.e. they react with both acids and bases, giving different kinds of salt along with water. So you see, the oxides of these metals are not obviously called ‘basic’ ones. We just call them amphoteric oxides.
18.PH is the meaure of how acidic or basic a solution is on the basis of hydrogen ion concentration.
(a)more than 7
(b)7(nuteral)
19.Metal compund A is sodium carbonate or sofium hydrogen carbonate.
Reaction involved:
Na2CO3+2HCL=2NaCl+CO2+H2O
20.The salt is Sodium hydrogencarbonate or baking soda.
Formation of sodium hydrogen carbonate:
NaCl+NH4+CO2+H2O=NaHCO3+NH4Cl
Its Uses:
(1)It is used in soda acid fire extinguisher.
(2)It is used for making baking Powder.
21.Plaster of paris.(CaSO4.½H2O)
22.Sodium Hydroxide and Carbonic Acid.
NaOH+H2CO3=NaHCO3+H20
Ph of Sodium hydrogencarbonate is 14.