Chemistry (Coordination Compounds)

12th CBSE Question Paper

One marks Questions

Q.1 What is the coordination number of metal ion in  [Fe(C2O4)3]3-

Q.2   Give an example of linkage isomerism.

Q.3   How if the magnitude of CFSE affected by nature of legend and oxidation state of metal ion?

Q.4    Illustrate with example ionization isomerism in             coordination compounds.

      Two marks Questions

Q.5    Write the isomers, name of isomerism and IUPAC name   of one of isomer of  [Cr(NH3)4Cl2]+

Q.6      Write the chemical formula of following:

(i)  Hexaammineplatinum           (ii) chloride                            (iii) tetraamminedichloridocobalt       (iv) ion

Q.7      Write the IUPAC name of following complexes:

             (i) [Ni(H2O)6](ClO4)2     (ii) [Co(NH3)5NO2]+2                 (iii) [Pt(NH3)4Cl2]Cl2     (iv) Na3[Cr(OH)2F4]

Three marks Questions

Q.8  Using the valance bond theory explain the geometry and magnetic nature of [Co(NH3)6]3+

Q.9  Write the IUPAC name and possible optical isomers of [CrCl3(en)(NH3)2]+

Q.10 Compare the magnetic behavior of [Fe(CN)6]4- and [FeF6]3-

Q.11    (i) On the basis of CFT write the electronic configuration of d4 ion if CFSE is less than pairing energy.

            (ii) Write the structure and name of all stereoisomers of the following:

(a)     [Co(en)3]Cl3          (b) [Fe(NH3)4Cl2]Cl

Evolution of Quantum Concept

In 1922, Niels Bohr won the Nobel Prize for Physics. He won it “for his services in the investigation of the structure of atoms and of the radiation emanating from them.” Naturally then, his Nobel Lecture, which he delivered on December 11, 1922, discussed the field of physics to which his work belonged. His lecture was titled “The structure of the atom.” He therefore spoke about the structure of the atom and how he had been able to modify the planetary model of Ernest Rutherford to account for the hydrogen spectrum. By doing this, he had become the first to apply the quantum concept, which restricts the energy of a system to certain discrete values, to the problem of atomic and molecular structure.

Indications of New Physics

Indications of New Physics in European Organisation (CERN)

Science Coaching India explore the NEWS   pertain to physics indications of new physics in CERN. The LHCb experiment in European organisation for nuclear research (CERN) has shown a feeble but persistent sign of physics that contradicts a basic assumption of the Standard Model of particle physics, indicating that this theory which has ruled the roost may not be complete in itself. Experts feel that this is a very big discovery. At the subatomic level, there are two types of processes that have been compared by the physicists at LHCb. One is the decay of what is called a B meson into an excited K meson and a pair of muons (muon-plus and muon-minus). The other is where the B meson decays into K meson giving an electron-positron pair. According to the standard model, since the muons and electrons are identical except for their masses, the rates of these two reactions should be the same. However, the carefully done experiment finds the rates are quite different. The researchers have taken care to factor out all the experimental error possibilities.

Need of Skill & Coaching

There are lot of students who decide to pursue their further studies in science field. They many opt for engineering or medical stream. However, to be successful in any of the streams, it is very important that students have good understanding about the fundamental concepts of the subjects.

Some schools appoint good and learned faculty or teachers to teach students. Such teachers work really hard to make sure that each student has grasped the concept well. However, not all the educational institutes lay that much emphasis on hiring qualified and learned teaching staff. In such scenarios, students should join science coaching classes at very initial stage itself.

It is suggested that student joins science coaching as early as possible so that he/she gets adequate time to understand, learn and improve his/her skills. It requires lots of practice to understand the concepts of science. Therefore, it will be beneficial for students if they get adequate time to practice.

Science coaching classes emphasize on teaching the fundamental concepts in the best possible way. They hire highly qualified faculties to teach students. They also conduct assessments on regular basis which are helpful in tracking the students



Science Coaching India explore, how can Talent Search Examinations help Students ?

The Strategy for Talent Search:

Ambitious XII Appeared / Pass Students, generally have reasonable understanding of most concepts but they do not have perfection in applying these concepts to solve examination-based problems. Even among extremely well prepared & deserving Students, a large percentage fail due to lack of proper Examination Temperament.

This will help them to know what they can achieve & how they came bridge the gap between their desire and aspiration. Based on their answers, Students will get suggestions to plug loopholes to perform to their optimum.

Preparing well for a particular Examination is one thing and transforming the knowledge & skills into success on the Examination day is another. Many Students are not able to adopt the right approach and proper examination temperament as they do not have the right feedback on their preparation.

This strategy help students to analyze & realize causes of failure in Examination and provide opportunity to learn from the experience of the successful Students and teach you how not to fail in Examination. This strategy will also boost your motivation & help you choose the right study material, books & provide assistance for preparation. If you take this seriously, you will learn what you need to do to succeed & get a good Rank in Examination.

Science skilling of India

PSLV all set to ferry 31 satellites on January 12 by Cartosat-2F aimed at surveillance will be main payload. Among the world’s favourite and reliable commercial launchers for small satellites, the upcoming 42nd PSLV will carry a total of 31 satellites including 28 paid riders. The main payload, the 710-kg Cartosat-2F, is the seventh in the Cartosat-2 series and is built to work for five years. ISRO is putting up two of its own small satellites — a 100 kg micro satellite and the 11-kg nano satellite INS-1C. There are also 28 smaller customers.The commercial satellites include three 100-kg class micro satellites and 25 nanosats (1-10 kg) from Canada, Finland, France, Korea the U.K. and the U.S.The PSLV has so far launched 209 small and medium satellites for foreign countries and earned revenue for the commercial arm, Antrix Corporation Ltd. ISRO will be trying a two-orbit feat with the PSLV for the second time. On Friday, just after 17 minutes from take-off, the main satellite will be released first into a 505-km orbit, followed by 29 others. Almost 1.5 hours later, microsat will be released into a lower 359 km orbit. Between the two orbits, the engine in the fourth stage of the rocket will be re-started twice during the course. The flight lasting 2 hours and 21 minutes will be the longest of the PSLV, about six minutes longer than C-35 which was launched in September 2016.

Solid Chemistry
New Carbon Nano Tubes (CNT) Developed 
Science Coaching India finds from news pertain to solid chemistry in reference to Journal Science that Scientists have developed carbon nanotubes (CNT) over 50,000 times thinner than a human hair. These CNT can separate salt from seawater and may help solve the global water crisis. Increasing demands for fresh water pose a global threat to sustainable development, resulting in water scarcity for four billion people, researchers said. Current water purification technologies can benefit from the development of membranes with specialised pores that mimic highly efficient and water selective biological proteins. The nanotubes, hollow structures made of carbon atoms in a unique arrangement and are more than 50,000 times thinner than a human hair. The super smooth inner surface of the nanotube is responsible for their remarkably high water permeability, while the tiny pore size blocks larger salt ions. The narrow hydrophobic channel forces water to trans locate in a single-file arrangement, a phenomenon similar to that found in the most efficient biological water transporters. Computer simulations and experimental studies of water transport through CNTs with diameters larger than one nanometre showed enhanced water flow, but did not match the transport efficiency of biological proteins and did not separate salt efficiently, especially at higher salinities.

Surface chemistry

12th  CBSE Question Paper (Topic:  Surface Chemistry)

One marks Questions

Q.1      Define Electrophoresis.

Q.2      Why is adsorption always exothermic 

Q.3      What is emulsion?

Q.4      Write the reason for stability of sols.

Q.5      In what way is a sol different from gel?

Q.6      How does soap help in washing clothes?

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