Bihar STET Paper 2 Chemistry Mock Test - 10 - Bihar PGT/TGT/PRT MCQ

Benzene diazonium chloride is hydrolysed to phenol when heated with water.
ArN₂Cl + H₂O ----> ArOH + N₂ + HCl 

For the spectral line in H -atom and H -like species (one electron)

For Lyman series
For shortest wavelength (maximum wave number) n₂ → ∞



For longest wave length (minimum wave number), n₂ = (n₁, + 1).
For Balmer series, n₁ = 2

BeO is amphoteric as it can react with both acids and base
BeO₊₂NaOH = Na₂BeO₂
BeO+H₂SO₄ + BeSO₄ + H₂O
On the other hand, MgO and Cao are metallic oxides and act as a base only.

The correct answer is option A
For the reaction rate of disappearance of A is related to rate of appearance of B by the expression:

Structure (a) = structure (c) and, structure (b) = structure (d)

For C₃H₈ : 3C + 4H₂ → C₃H₈ ; ∆H₁
For C₃H₈ : 2C + 3H₂ → C₂H₆ ; ∆H₂
∆H₁ = -[2(C-C)+8(C-H)]+[3C_s→g+4(H-H)]     -(I)
∆H₂ = -[1(C-C)+6(C-H)]+[2C_s→g+3(H-H)]     -(2)
Let bond energy of C-C be x kcal and bond energy of C-H be y  kcal.
From eqn I and 2
 ∆H₁ = -[2x+8y]+[3×172+4×104]     -(3)
∆H₂ = -[x+6y]+[2×172+3×104]     -(4)
Also given, C+O₂ → CO₂; ∆H = -94.0 kcal     -(5)
H₂ + ½ O2 → H₂O ; ∆H = -68.0 kcal      -(6)
C₂H₆ + 7/2 O₂ → 2CO₂ + 3H₂O ; ∆H = -372 kcal     -(7)
C₃H₈ + 5O₂  → 3CO₂ + 4H₂O ; ∆H = -530 kcal-(8)
By inspection method,2 × (5) + 3 × (6) - (7) gives
2C + 3H₂ → C₂H₆ ; ∆H₂ = -20 kcal
And  3×(5) + 4×(6) -(8)
3C + 4H₂ → C₃H₈ ; ∆H₃ = -20 kcal 
By eqn. (3), (4), (9) and (10)
x+6y = 676
2x+8y = 956
x = 82 kcal and y = 99 kcal

Total order of reaction = order wrt to A + order wrt to B.

The correct answer is Option C.

Mass % of H2SO4=29%
Therefore 100g solution contains 29g H2SO4
​
Let the density of solution (in g/ml) is d
Molarity of solution :

Hence the answer is 1.22g/ml.
 

Bohr Model of atom:

• An atom is made up of three particles: Electrons, neutrons and protons.
• The protons and neutrons are located in a small nucleus at the centre of the atom.
• The electrons revolve rapidly around the nucleus at the centre of the atom.
• There is a limit to the number of electrons that each energy level can hold.
• Each energy level is associated with a fixed amount of energy.
• There is no change in the energy of electrons as long as they keep revolving in the same energy level.

Bohr explained the stability through the concept of revolution of electrons in different energy levels.

The change in the energy of an electron occurs when it jumps from lower to higher energy levels. When it gains energy, it excites from lower to higher and vice versa.
Thus energy is not lost and the atom remains stable.

a) More molar mass, more entropy. So ∆_SN2O4 > ∆S_NO2
b) CO₂ has more entropy than dry ice at -78°C
c) Pure alumina iss crystalline solid while ruby is amorphous. And ∆S_amorphous > ∆S_Crystalline. So alumina has less entropy than ruby.
d) At lower pressure, entropy be higher as gas particles are far from each other. So (∆S_N2)1 _bar > (∆S_N2)_{5 bar} 
 

For boiling point, we have to consider both branching and Molecular mass. In 4  bromopentane molecular mass is nearly the same as compared to 3 chloro pentane but we have 3,3-dichloropentane extended into 2 directions so the boiling point of 3,3-dichloropentane will be more and the other order will be followed by option C.

If (2s-2p) mixing is not operative, then

[Pt(NH₃)₄]Cl₄ → 5 ions
[Pt(NH₃)₂Cl₄] → 0 ions
[Pt(NH₃)₄Cl₂]Cl₂ → 3 ions

The correct answer is B
Halogens have maximum negative electron gain enthalpy in the corresponding periods. This is due to the fact that the atoms of these elements have only one electron less than stable noble gas configurations. Electrons gain enthalpy of the elements of the group becomes less negative down the group. However, the negative electron gain enthalpy of fluorine.

Questions take learning forward by interactions and lead to conceptual clarity. Thus, students should be encouraged to ask the questions. Question-asking puts advanced cognitive demand on students. It encourages students to think beyond literal questions.

The instructions of a teacher must be based on the child's abilities, aptitude and interest. His ability to grasp and apply things, his natural ability to justify learning and his interest to learn a particular thing could decide the teaching strategies, as the education these days has become more child-centered. The teacher must be aware of the child's abilities, aptitude, and interest, which is possible only through proper evaluation.

Herbart advocated five formal steps in teaching:

1. Preparation—a process of relating new material to be learned to relevant past ideas or memories in order to give the pupil a vital interest in the topic under consideration;
2. Presentation—presenting new material by means of concrete objects or actual experience;
3. Association—thorough assimilation of the new idea through comparison with former ideas and consideration of their similarities and differences in order to implant the new idea in the mind;
4. Generalisation—a procedure especially important to the instruction of adolescents and designed to develop the mind beyond the level of perception and the concrete;
5. Application—using acquired knowledge not in a purely utilitarian way but so that every learned idea becomes a part of the functional mind and an aid to a clear, vital interpretation of life. This step is presumed possible only if the student immediately applies the new idea, making it his own.

Best speech habits are developed in language labs. Thus, to develop good speech habits in the learners, he should exploit language labs. Language labs involve students in language learning exercises more actively and also let them participate more as compared to a traditional classroom setting.

Activity-based learning is a ‘learner-centred’ approach in the teaching-learning process. In this approach, the ‘learner’ or ‘child’ and not the ‘teacher’ is the main focus of the educational program. It emphasizes ‘learning’ rather than ‘teaching’.

• Activity-based learning integrates multiple methods of teaching like Demonstration, Role-play, Brainstorming, Project method, Debate, etc.
• Activity-based learning brings the real issues and problems from day-to-day life in classroom settings.
• It provide provides opportunities to apply multiple senses.
• It includes all objects, events, natural phenomena and social surroundings in the teaching-learning process.
• It clarifies abstract concepts, develops concrete thinking and brings reality in real settings.
• During activity-based learning, the learners use his/her multiple senses to understand the concepts and enhance learning.
• It arouses the child’s interests, abilities, and needs during the learning process.

Hence, we conclude that all the above points are the advantages of the activity-based learning.

The correct answer is Federal.

Key Points

• 'Federal' is NOT mentioned in the Preamble of the Constitution of India.
• The Preamble of the Constitution of India provides for the liberty of thought, expression, belief, faith and worship.
• The ideals behind the Preamble were laid down by Jawaharlal Nehru’s Objectives Resolution, adopted by the Constituent Assembly on January 22, 1947.
• The Preamble's Four Components are:
  • It states that the Constitution's source of authority lies with the people of India.
  • It declares that India is a country that is Sovereign, socialist, secular, democratic and republic.
  • It sets out its priorities of maintaining justice, freedom and equality for all people and fostering fraternity in order to preserve the nation's unity and dignity.
  • It cites the date on which the constitution was adopted (November 26, 1949).

An Se-young of South Korea won the gold medal in the women's singles event at the 2023 World Badminton Championships, defeating Carolina Marín of Spain in the final, 21-12, 21-10. An Se-young, aged 21, became the first woman from South Korea to win the world singles title. She had a dominant tournament, winning all of her matches in straight games, including victories over Olympic champion Chen Yufei and two-time world champion Akane Yamaguchi.

Weighing nearly a trillion metric tonnes and covering an extensive area of 4,000 square km, the colossal iceberg A23a, originating from West Antarctica's Filchner-Ronne Ice Shelf in 1986, has broken its decades-long stillness, marking a noteworthy event in its movement after more than 30 years.

Unstructured observation is an important tool for collecting assessment data because it does not interrupt the daily life of classroom- thereby being strong on reliability and validity. An unstructured observation records incidents that take place spontaneously. This observation must be shared with the parents and the learners.
Formal tests, Examinations, and Pass or fail categories for primary students may not help the student to learn. These enhance rote memorization, which is not the motive of teaching.

A, B and D are the correct options because we can write only because of friction between the tip of the pen and the paper. We can walk because of the friction between our feet and the ground. We are able to stop a moving vehicle by applying brakes because of friction.

18% of x = 13.50% of y

50% of x = 37.50% of y
Hence, Option D is correct.