Kerala Plus One Chemistry Answer Key 2021 (Available) – Download Question Paper, Answer Key Pdf Here

Kerala Plus One Chemistry Answer Key 2021 – Students who appeared for the Kerala Plus One Chemistry exam on September 28 can check the question paper, and answer key from this page. The First-year students are going to appear for the Higher Secondary examination (Plus One) from September 24, 2021, and will end on October 18, 2021. With the help of the Kerala Plus One Chemistry answer key, students can cross-check their answers and calculate their probable score before Kerala Plus One result 2021 is announced. The question papers and answer keys for the First Year Higher Secondary Public Examination can also be checked online at the official website of DHSE – dhsekerala.gov.in. As and when they are released, it shall be made available in pdf format For more details on Kerala Plus One Chemistry Question Paper, Answer Key 2021, scroll down the page below.

Latest: Kerala Higher Secondary First Year (Plus One) Chemistry Answer Key 2021 is now available. Students can check it from the links given below.

Kerala Plus One Answer Key 2021

DHSE also publishes the official answer key for the Plus One September examinations. It is crucial for the students to verify their answers so that they can estimate their tentative marks in the examination. Students can check the Kerala Plus One answer key 2021 for Chemistry Paper held on September 28, 2021, from below.

Click Here to download Kerala Plus One Chemistry Question Paper & Answer Key 2021.

Ques. Write the orbital representation for the following quantum number: 

1. n = 3, l = 1 
2. n = 5, l = 0 

Ans. (a) 3p, (b) 5s

Ques. Identify the correct electronic configuration of Cu(z = 29) from the following and give the reason for your answer. 

1. Cu – 1s²2s²2p⁶3s²3p⁶3d¹⁰4s¹
2. Cu – 1s²2s²2p⁶3s²3p⁶3d⁹4s²

Ans. Correct answer is an option (a). This is because fully filled d orbitals are more stable than incompletely filled d-orbitals are more stable than incompletely filled d-orbits to 3d orbital to give a more stable configuration.

Ques. Fill in the blanks:

Molecule	Structure	Bond angle
BF3	________	120o
BeCl2	Linear	________

Ans. Trigonol planar, 180^o

Ques. Write any postulates of Kinetic Molecular Theory of gases.
Ans. Postulates of the kinetic theory of gas

• The molecules in a gas are small and very far apart.
• Most of the volume which a gas occupies is empty space.
• Gas molecules are in constant random motion.
• Just as many molecules are moving in one direction as in any other,.
• Molecules can collide with each other and with the walls of the container.
• Collisions with the walls account for the pressure of the gas.
• When collisions occur, the molecules lose no kinetic energy; that is, the collisions are said to be perfectly elastic.

Ques. Write Hess’s law of constant heat summation.
Ans. Hess’s Law of Constant Heat Summation states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes.

Ques. Write an expression for equilibrium constant (K_C) for the following reactions:
(a) N_2(g)+3H_2(g) ↽⇀ 2NH_3(g)
(b) H_2(g) + I_2(g) ↽⇀ 2HI_(g)

Ans. (a) K_C = [NH₃]² / [N₂] [H₂]
(b) K_C = [HI]² / [H₂] [I₂]

Ques. What are buffer solutions? Given an example for buffer solution.

Ans. A buffer solution is one that maintains its pH fairly constant even upon the addition of small amounts of acid or base. One common example for buffer solution is a weak acid together with a salt of the same acid with a strong base. These are called acid buffers,  (eg): CH₃​COOH+CH₃​​COONa .

Ques. (i) Write the chemical name of Baking soda.
(ii) Name the product formed when Washing Soda is heated above 373K.

Ans. (i) Sodium bicarbonate
(ii) Soda ash

Ques. Write the position isomers of alcohol with the molecular formula C₃H₈O.
Ans. 3 isomers (1-propanol, 2-propanol, ethyl-methyl ether)

Ques. Write the complete structural formula and condensed structural formula of 2-Methylpentane.
Ans. C₆H₁₄ – PubChem

Ques. Write A and B in the following reactions:
(a) 3CH = CH – red hot iron tube, 873 K gives product A
(b) 2CH₃Cl + 2Na – dry ether gives product B

Ans. (a) Benzene, (b) Ethane

Ques. Write the geometrical isomers of But-2-ene.

Ans.

Ques. (i) Write Avagadro number.
(ii) How many moles of water molecules are present in 180 g of water? (Molecular mass of water is 18 g)

Ans. (i) Avagrado number is 6.02214076 × 10²³
(ii) Moles of water =180 / 18= 10 mole

Ques. (i) Define Molarity.
(ii) State law of multiple proportions.

Ans. (i) The number of moles of a solute dissolved in 1 L (1000 ml) of the solution is known as the molarity of the solution.
(ii) The law of multiple proportions states that when two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.

Ques. Account for the following:
(i) Atomic radius increases from top to bottom in a group.
(ii) Electron gay enthalpy of F is lower than that of Cl.

Ans. (i) It’s true that the atomic radius of atoms generally increases from top to bottom within a group. As the atomic number increases down a group, there is again an increase in the positive nuclear charge. However, there is also an increase in the number of occupied principal energy levels.
(ii) Fluorine atom is small in size and suffers from interelectronic repulsions between seven valence electrons. The added electron experiences much repulsion on smaller F. Hence its electron gain enthalpy is less.  

Ques. (i) Depending upon the type of atomic orbital being filled with electrons, the elements are classified into four blocks. Name these four blocks of elements.
(ii) State the modern periodic law of elements.

Ans. (i) They are s, p, d, and f-block elements.
(ii) The chemical and physical properties of elements are a periodic function of their atomic numbers.

Ques. (i) What is the bond order according to M.O. theory?
(ii) He₂ molecule does not exist, why?

Ans. (i) As per the molecular orbital theory, bond order is also defined as the difference, divided by two, between the number of bonding and antibonding electrons.
(ii) According to the molecular orbital theory He has two electrons in the outermost shell and thus it is chemically stable because its duplet is complete. Hence it does not participate in the bond formation and the molecule must have a bond to exist which is not in the case of Helium.

Ques. (i) Compressibility factor of an ideal gas is ____.
(ii) At 25^oC and 760 mm of Hg pressure a gas occupies 600 mL volume. What will be its pressure at the height where the temperature is 20°C and volume of the gas 660 mL.

Ans. 1
(ii) 56.97 mm Hg

Kerala Plus One Answer Key 2021 Overview

Name of the board	Directorate of Higher Secondary Education (DHSE) Kerala
Examination Name	Higher Secondary Kerala First Year September / October 2021
Class	Plus One (+1) / Class 11th
Exam Date	24 Sep to 18 Oct 2021
Mode of exam	Offline

How to Download DHSE Kerala Class 11th Answer Key 2021?

To download the answer key for Kerala Plus One September 2021 exam, students may follow the steps given below.

1st Step: Click on the direct link on the page above to download the answer key.

2nd Step: After you do so, the answer key will appear on the screen.

3rd Step: Candidates can then use it to cross-check their answers and calculate their marks in their respective papers.

Kerala First Year Secondary 2021 Chemistry Exam Pattern

After the candidates have downloaded the answer key, it is important that you know the exam pattern and marks distribution. This will come in handy for assigning marks to yourself as you are cross-checking your answers with the answer key provided. Check the complete marks distribution for the Kerala Plus One Chemistry paper from the table below.

No. of questions	Marks Allotted
From 1 to 12 (Answer any 6 questions)	2 marks each
From 13 to 28 (Answer any 8 questions)	3 marks each
From 29 to 40 (Answer any 6 questions)	4 marks each

Kerala Plus One Result 2021

The Department of Higher Secondary Education, Kerala releases the results for the class 11th examination online at its official website. The students can check their DHSE +1 Result 2021 using the login details like their roll number and school code. Besides the individual result, students can also check the school-wise result by using their school code. A large number of students appeared for Kerala Plus one examination held in September. The result is prepared based on the students’ performance in the examination. Students are promoted to Plus Two (Class 12th) based on their marks in the Plus one examination.