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Chemistry Chapters

9th Class Chapter 8 Chemistry Long Questions

Dear students, prepare for chemistry class 9th chapter 8 long questions. These important long questions are carefully added to get you best preparation for your 9th class chemistry ch. 8 exams.
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Question: 1
Q no<gwmw class="ginger-module-highlighter-mistake-type-6" id="gwmw-15862539400918371676995">:</gwmw>6 (A) Compare the chemical properties of alkali and Alkaline earth metals.
Answer: 1
1-16
ALKALI METALS:
1- Occurrence.
They are very reactive and always occur in combined form.
2- Eelectropositivity:
These are highly They have ionization energy values.
3- Reaction with water:
They react with water vigorously at room temperature to give strong alkaline solution and hydrogengas
2na+2H2O ______>2NaOH + H2
4- Reaction with carbon:
They do not react with carbon directly
5- Reaction with Nitrogen
They do not form nitrides directly

ALKANLINE EARTH METALS:
1- Occurrence:
They are fairly reactive and also occur in combined form
2- Electropositivity:
They are less electro positive. They have ionization energy values
3- Reaction with with water:
They react with waterless vigorously and on heating they produce
Mg + H2O_____> MgO + H2
4- Reaction with Nitrogen:
They form stable nitrides when heated with nitrogen
5- Reaction with carbon:
They give stable carbide on heating with carbon A+2c ____>2
Question: 2
Q no 5 (B) Write four chemical properties of <gwmw class="ginger-module-highlighter-mistake-type-1" id="gwmw-15862542584209897950461">Non-Metal</gwmw>.
Answer: 2
2-16
Silver is white, lustrous metal. It is an excellentconductor of heat and electricityIt is also highly ductile and malleable metals, It's polished surface are good refllectedof light formation of thin layer of oxide or sulphide on it's surface makes it relatively unreactive. Under normal conditions of atomosphereair does not affect silver. It tarnishes in presence of sulfhercontaningcompound like H2S.
Question: 3
Q no: 6<gwmw class="ginger-module-highlighter-mistake-type-6" id="gwmw-15862550263201604472289">(</gwmw>A) What are the relationships betweenelectro positivity and ionization energy?
Answer: 3
3-16
Electro positive character depend upon the ionization energy which in turn depend upon size and nuclear charge of the atom small sized atoms with high nuclea charge have high ionization energy value. In this way atoms having high ionization energy are less electro positive or metallic that is the reason altali metals have the larges size and the lowest size ionization energy in their respective periods. Therefore they have the highest metallic character.
Question: 4
Q no<gwmw class="ginger-module-highlighter-mistake-type-6" id="gwmw-15862558201130604891168">:</gwmw>6<gwmw class="ginger-module-highlighter-mistake-type-6" id="gwmw-15862558201133942616488">(</gwmw>B) Write a note of silver.?
Answer: 4
4-16
Silver is white lustrous metal. It is an excellentconductorof heat and electricity It is also highly ductile and malleable metals , It's polished surface are food reflectedof light formation of thin layer of oxide or sulphideon it's surface makes it relatively unreactive. under normal conditions foatmosphere air does not affectsilver. It tarnishes in presence of sulpher containingcompound like H2S.
Question: 5
Q no<gwmw class="ginger-module-highlighter-mistake-type-6" id="gwmw-15862567953459924866919"> :</gwmw>7 (B) Write the Physical characteristics of Metals?
Answer: 5
5-16
Almost all metals are solids the have high melting and boiling points.
They process metallic luster and can be polished.
They are good conductor of heat electricity.
They have high densities
They are hard ( except sodium and potassium)
Question: 6
Write detail note on metals
Answer: 6
6-16
Metals are the elements with are electropositive and from cations by losing electrons. Metals can be categorized as
Types of metals:
  1. Very reactive metals potassium, sodium , calcium, magnesium and aluminum.
  2. Moderately reactive: zinc, iron, tin, and lead.
  3. Least reactive or noble: copper , mercury , silver and gold.
Question: 7
What is electropositive character? Giving its rend in periodic table.
Answer: 7
7-16
Definition: metals have the tendency to lose their valence electrons and form cations by losing electrons. This property of a metal is termed as electro positivity or metallic character.
Question: 8
Give chemical properties of metals.
Answer: 8
8-16
Comparison between alkali metals and alkaline earth metals :
Alkali metals:
  • Occurrence : they are very reactive and always occur in combined form
  • Electro-positivity: they are high electropositive. They have ionization energy value ranging from 520KJ mol-1 for Li to 376 KJmol-1 for Cs
  • Reaction with water: the react with water vigorously at room temperature to give strong alkaline solution
  • Reaction with O2:they immediately tarnish in air giving their oxides which form strong alkalis in water.
  • Reaction with H2: they form ionic hydrides with H2 at high temperature
  • Reaction with Halogens: they react violently with halogens at room temperature to give halides
  • Reaction with N: they do not form nitrides directly
  • Reaction with C: they do no react with carbon directly
Question: 9
What are the uses of alkali and alkaline earth metals?
Answer: 9
9-16
Use of Sodium:
  1. Sodium-potassium alloy is used as a coolant in nuclear reactors
  2. It is used t o produce yellow light in sodium vapor lumps
  3. It is used as reducing agent in the extraction of metal like Ti
Question: 10
What is inertness of noble metals and what are their uses?
Answer: 10
10-16
Inertness of noble metals: Elements in which d-orbital are in the process of filling constitute a group of metals called transition metals or d group elements. They exhibit a variety of oxidation states transition metals of 4th, 5th and the 6th period of the periodic table.

Question: 11
What are non-metal and write their physical properties?
Answer: 11
11-16
Definition: non metals form negative ions by gaining electrons. In this way non-metals are electronegative in nature and form acidic oxides.

Question: 12
What are chemical properties of non-metals?
Answer: 12
12-16
Chemical properties of non metals:
  1. Their valence shells are deficient of electrons, therefore, they readily accept electrons to complete their valence shell and become stable.
  2. They form ionic compounds with metals and covalent compounds by reacting with other non-metals e.g. CO2 and NO2 etc.
  3. They usually do not react with water
  4. They do not react with dilute acids because non-metals are itself electron acceptors
Electro-negativity of first number of group 14, 15, 16 and 17 and higher than that of other members of the group decreasing trend of electro-negativity
F>O>Cl>N>Br>S>C>I>P
Question: 13
Give comparison of reactivity of halogens?
Answer: 13
13-16
Definition: elements of group-17 of the periodic table consist of fluorine, chlorine, bromine, iodine and astatine. They are collectively called halogens.
Explanation: fluorine and chlorine exist as diatomic gases at room temperature. Interestingly, they intermolecular forces of attraction increases downward in the group due to increase in size of atom. Due to this reason bromine exist as a liquid, and iodine as a salt.
Question: 14
What are important reactions of halogens?
Answer: 14
14-16
  • Oxidizing properties: all halogens are oxidizing agents . Fluorine is the strongest oxidizing element while iodine is the least i.e. is mild oxidizing agent. Fluorine will oxidize any of halide ion(X-) in solution an changes itself to F ion. Similarly , chlorine will displace Br- and I- ion from their salt solutions and oxidize them to Bromine and iodine.
Question: 15
What are important reactions of halogens
Answer: 15
15-16
  • Oxidizing properties: all halogens are oxidizing agents . Fluorine is the strongest oxidizing element while iodine is the least i.e. is mild oxidizing agent. Fluorine will oxidize any of halide ion(X-) in solution an changes itself to F ion. Similarly , chlorine will displace Br- and I- ion from their salt solutions and oxidize them to Bromine and iodine.
Question: 16
Give significance or important non-metals?
Answer: 16
16-16
Although non-metals are fewer than metals, yet they are highly significant. They are equally important for human beings, plants and animals in fact, life would not have been possible without the presence of non-metals on earth.