Manish Mehta(MRM)

HALOALKANES The compounds of hydrocarbons (saturated) containing Halogen (X) attach with them in SP 3 Hybridisation state is known as “ HALOALKANES ”  They are considered to be ionic in nature because of the presence of Halogen gp attached.  They can be categorised into following three types depending upon the number of #Alkyl gps attached with the Carbon bonded to Halogen directly. Chemistry of HALOALKANES in terms of their physical properties is not much complex, their Physical properties are; • Melting and Boiling points • Density  • Solubility , etc... Boiling point of HALOALKANES is higher , if the molecules mass of the compound is high. Usually the increase in branching decreases the surface area and thus decrease the boiling point too.

#JEE NEWS (2017) The Ministry of Human Resource Development, Government of India has notified following two changes in the JEE pattern for 2017: ■ There shall be no weightage for the 12th class marks in calculating the ranks in the JEE (Main) examination , ■ For the candidates to qualify for the admission in the IITs/NITs/IIITs and such other CFTIs whose admissions are based on the JEE (Advanced)/JEE(Main) ranks, they should have secured at least 75% marks in the 12th class examination, or be in the top 20 percentile in the 12th class examination conducted by the respective Boards. For SC/ST students the qualifying marks would be 65% in the 12th class examination. The States of Madhya Pradesh, Haryana, Uttrakhand, Nagaland, Odisha & some other institutions have joined JEE (Main) system, however, their admission criteria will be notified by the concerned authorities. Therefore, the candidates seeking admission to the institutions in these states, which were...

Students appearing for Class X board exams from next year will have to study six subjects instead of five with the Central Board of Secondary Education (CBSE) remodelling its assessment scheme. Class X students have to presently study five subjects—two languages, social science, mathematics and science. Students also have a choice of studying a vocational subject as an “additional” course. However, from the 2017-18 academic year, it will be compulsory to study a vocational subject.

The term nuclear_charge is use to define the effective force over the outermost electron present in the valence shell of an atom. The consideration of #Nuclea r_charge is just as an imaginary line if force which tends to hold up the electrons more effectively so that the magnitude of # Atomic_size decrease and this in turn affects the other # periodic_properties of the elements. With the increasing value of #Nuclear_charge the inward pull💪 to the electrons increases and thus size decreases.👇👇

A chemical reaction is said to Nucleophilic type if the attack of a positive charge loving specie takes place over it. There are generally two types of reactions for this category ; ● SN1 reaction ● SN2 reaction # SN1 》a reaction is said to be SN1 type if it does involves the nucleophilic substitution by unimolecular type. In SN1 reactions the generation of carbocation takes place in the very first step then the attack of nucleophile takes place. They involves the complete retention of symmetry. Although inversion of symmetry also occur but the major product is always with the retention of symmetry... It involves the presence of Base in the first step. The order of reactivity is 3°>2°1 ° since the carbocation generation occur. # SN2 》a reaction is said to be of SN2 type if it does involves the nucleophilic substitution of bimolecular type. This reaction is of 1 step only since the attack of nucleophile as well as the removal of le...

Nucleic Acids are defined as the biomolecules, polymers present in the living system. They are also called #polynucleotides since the repeating unit of nucleic Acids is nucleotide. Each nucleotide is made up of three parts ● a sugar molecule           ●  a heterocyclic nitrogenous Base           ●   a phosphoric acid group Thus in general a nucleotide may be represented by the figure below  #MRM

Photoelectric effect ; when light of certain frequency strikes the surface of a metal, electrons are ejected from the metal surface. This phenomena is called photoelectric effect.  Cesium, which amongst the alkali metals has the lowest ionisation energy is metal from which electrons are ejected most easily by light. This metal is used in making electric cells.  Observation regarding photoelectric effect are;  1) for each metal, a certain minimum frequency of incident light is needed to eject electrons. This is known as threshold frequency.  2) The no.of ejected electrons from metal surface depends upon the intensity of incident radiations.