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the hybridization of boron in BF3 is sp²

Forboronto bond with three fluoride atoms inborontrifluoride (BF3), the atomic s- and p-orbitals inboron'souter shell mix to form three equivalent sp2 hybrid orbitals

the correct answer is option (c)8 because 4 are visible and other four are from the two C-N triple bonds with two from each.

central carbon is sp hybridised and other 2 are sp2 hybridised

to know this,use dirty method:

count the number of atoms bonded with required atom and calculate:

2 atoms bonded: sp3 atoms bonded: sp24 atoms bonded: sp3

dirty method is valid for calculating hybridisation of carbon only

zeolite catalyst(HZSM-5).

Zeolite, any member of a family of hydrated aluminosilicate minerals that contain alkali and alkaline-earth metals. The zeolites are noted for their lability toward ion-exchange and reversible dehydration. They have a framework structure that encloses interconnected cavities occupied by large metal cations (positively charged ions) and water molecules.

Demerits of Mendeleev Periodic Table:1) He was unable to locate hydrogen in the periodic table. 2) Increase in atomic mass was not regular while moving from one element to another.3) The number of elements yet to be discovered was not predictable.

answer is for 3 marks

Themercury-in-glassormercury thermometerwas invented by physicistDaniel Grabreil FahrenheitinAmsterdam(1714). It consists of a bulb containingmercury attached to aglasstube of narrow diameter; the volume of mercury in the tube is much less than the volume in the bulb. The volume of mercury changes slightly with temperature; the small change in volume drives the narrow mercury column a relatively long way up the tube. The space above the mercury may be filled withnitrogengas or it may be at less thanatmospheric pressure a partialvacuum.

the zeolite needs to be regenerated. Brine solutions are passing through the bed of inactivated zeolite. The following reactions are taken place and form Na2Ze.CaZe + 2NaCl → Na2Ze + CaCl2

Demerits of dobereiner’s triads system:

-This system fails because it does not hold good for all the elements discovered till date time. It is limited to only few elements.

-It does not completely explain the complete properties of elements like valency, oxidation state of elements which have variable oxidation state like phosphorus showing trivalent and pentavalent nature.

-It does not fit to transition elements.

The only advantage of Dobereiner’sresearch was that it made chemists look at elements in terms of groups of elements with similar chemical and physical properties. This eventually led to rigorous classification of elements and the modern periodic table of elements, as we now know it, was discovered.

The property of gases by which aquatic animals and plants breathe is diffusion as the oxygen diffuse in the water helping them to breathe.

name two gases used by aquatic plants that are soluble in water

GSM-5 is a synthetic Zeolite used for converting alcohols to gasoline.

It is in your book see back page

0.25/56 × Na = 1/896 × Na × A=> A = 896*0.25/56 = 4

=> A = 4

Fifth group,third period which is phosphorous

is these the right Ans

An atomic number represents the number of protons in the nucleus and valency number of a metal is defined as the measure of the number of chemical bonds the atoms of a substance can form.

The atomic number of the periodic table for M2O3 is 13 and valency number of the compound is 3.

Hence the metal is aluminum in the periodic table

Such level gauges are among the most commonindustrial uses of radioisotopes. Some machines which manufacture plastic filmuse radioisotopegauging with beta particles to measure the thickness of the plastic film. ... The detector signal strength isusedto control the plastic film thickness.

Radioactivity is used in industries in the following ways:

1) Knowing the penetrating power of Beta particles, they are used to control the thickness of paper.

2) Radio isotopes such as Uranium 235 are used as a fuel in atomic energy reactors.

3) The ionising effect of radiations from radioactive isotopes is used in making certain luminescent signs.

4) Radio isotopes are used by engineers in factories to avoid accumulation of charge on moving parts of machines due to friction.....

Indian society is consider as hierarchicalsociety.

Indian society is considered as a hierarchical society.

Indiais a hierarchicalsociety. Whether in northIndiaor southIndia, Hindu or Muslim, urban or village, virtually all things, people, and social groups are ranked according to various essential qualities. AlthoughIndiais a political democracy, notions of complete equality are seldom evident in daily life.

Indiais a hierarchicalsociety. Whether in northIndiaor southIndia, Hindu or Muslim, urban or village, virtually all things, people, and social groups are ranked according to various essential qualities. AlthoughIndiais a political democracy, notions of complete equality are seldom evident in daily life.

For a given alkyl group, alkyl iodide has the highest density; therefore the halide must be iodine. Since density decreases as the size of alkyl group increases; the alkyl must be methyl. Therefore, methyl iodide has the highest density among the alkyl halides.

An element is a substance whose atoms all have the same number of protons. The 3 different types of elements are : Metals, Non-metals, and inert gases. There are 118 different types of elements in the Periodic table.

an element is defined as the simplest form of pure substances which cannot be broken down into simpler substances by any physical or chemical reaction s.

Carbon-12 and carbon-14 are twoisotopesof the elementcarbon. The difference between carbon-12 and carbon-14 isthe number of neutronsin each atom. Atoms of both isotopes of carbon contain 6 protons. Atoms of carbon-12 have6 neutrons, while atoms of carbon-14 contain 8 neutrons. Aneutral atomwould have the same number of protons and electrons, so a neutral atom of carbon-12 or carbon-14 would have 6 electrons.

i) The atomic number is equal to the number of protons. Therefore, the atomic number of the atom is 8.

(ii) Since the number of both electrons and protons is equal, therefore, the charge on the atom is 0.

Carbon-12 and carbon-14 are twoisotopesof the elementcarbon. The difference between carbon-12 and carbon-14 isthe number of neutronsin each atom. Atoms of both isotopes of carbon contain 6 protons. Atoms of carbon-12 have6 neutron, while atoms of carbon-14 contain 8 neutrons. Aneutral atom would have the same number of protons and electrons, so a neutral atom of carbon-12 or carbon-14 would have 6 electrons.

an elementary particle or fundamental particle is a subatomic particle with no substructure, thus not composed of other particles

Thehydrogen atomcontains only two fundamental particles. b) Cathode ray particles i.e.,electrons, have constant charge to mass ratio for all matter.

option 2 is the answer.

The octet rule states that elements gain or lose electrons to attain an electron configuration of the nearest noble gas.

Incomplete Octet

There are certain atoms of certain elements that can exist in stable compounds forming bonds with less than eight valence electrons. When this occurs, the atom of the element within the molecule is said to contain an incomplete octet.

The common examples of such elements are hydrogen (stable with only 2 valence electrons), beryllium (stable with only 4 valence electrons) and boron and aluminum (stable with only 6 valence electrons). For hydrogen 2 valence electrons give it a noble gas structure (like He) so this is much like the octet rule for everything else below period 1.

Expanded octet:

Expanded octet occurs when an atom is able to have more than 8 valence electrons. For example, in SO₃, the sulfur atom forms 6 covalent bonds, hence it has 12 valence electrons. Expansion of octet is possible only from Period 3 elements onwards, due to the presence of low-lying empty d orbitals that can accommodate the extra electrons.

Plastic is a non-biodegradable material and as such it causes land pollution. At the same time burning such materials in the form of garbage causes serious air pollution. Some ways to limit its consumption are:

Reducing the use of plastics. Whenever possible use paper bags instead of plastic bags.

Reusing it for some other purpose thereby decreasing its consumption.

Recycling of plastic. It requires the plastic to be collected, sorted, chopped, melted and remoulded.

option b) An aquous solution of Na2CO3 is alkaline in nature. Therefore, its pH must always be above 7.

In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond.

Difference Between Aromatic and Aliphatic CompoundsDefinitionAromatic compounds contain an aromatic ring or ‘benzene ring’.

Aliphatic compounds are organic chemical compounds without benzene rings.

ReactionsAromatic compounds need special conditions to react.

Aliphatic compounds react more freely and easily.

TypesAromatic compounds are always cyclic as it contains the benzene ring as part of its structure.

Aliphatic compounds can be linear as well as cyclic.

Saturation PotentialAromatic compounds are always unsaturated.

Aliphatic compounds can be saturated as well as unsaturated.

ConjugationIn aromatic compounds, the benzene ring is conjugated due to the presence of alternating double bonds.

The majority of aliphatic compounds are not conjugated.

The metal-carbon bonds in metal carbonyls have both σ and π characters. A σ bond is formed when the carbonyl carbon donates a lone pair of electrons to the vacant orbital of the metal. A π bond is formed by the donation of a pair of electrons from the filled metaldorbital into the vacant anti-bonding π orbital (also known as back bonding of the carbonyl group). The σ bond strengthens the π bond and vice-versa. Thus, a synergic effect is created due to this metal-ligand bonding. This synergic effect strengthens the bond between CO and the metal.

Let the mass of the substance be x grams.

According to the law of conservation of mass, sum of masses of reactants = sum of masses of products=> X + 0.22 = 0.9+0.44=> X = 0.22+0.9=> X = 1.12 grams

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thank you!but you have written x=0.22+0.9,but where is 0.44

grams of potassium bromide = 7.25% of 250 = 7.25*250/100 = 18.125gm

option b) N3- because of vacant d orbital

octet rule: Atoms gain, lose, or share electrons with other atoms in order to fill their valence level with eight electrons.

since, nitrogen does not complete its octate in the covalent bond. option (4) is correct.

thnks

Octet rule is for there to be 8 electrons in the valence shell.

Duplet is 2 electrons in valence shell structure.

These are the stable electronic configurations resembling that of noble gases.

The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell. When atoms have fewer than eight electrons, they tend to react and form more stable compounds. It was postulated by Kossel & Lewis. The atoms complete their octet by either loosing or gaining of electrons. They do so to attain the nearest noble gas stable electronic configuration .The octet rule successfully explained the formation of chemical bonds depending upon the nature of the element.

Limitations of the octet theory:

1) The main limitation to the rule is hydrogen, which is at its lowest energy when it has two electrons in its valence shell. Helium (He) is similar in that it, too, only has room for two electrons in its only valence shell.

Hydrogen and helium have only one electron shell. The first shell has only one s orbital and no p orbital, so it holds only two electrons. Therefore, these elements are most stable when they have two electrons.

2) Second limitation are aluminum and boron, which can function well with six valence electrons. Consider BF3. The boron shares its three electrons with three fluorine atoms. The fluorine atoms follow the octet rule, but boron has only six electrons. Most elements to the left of the carbon group have so few valence electrons that they are in the same situation as boron: they are electron deficient.

c is the correct answer

co2 is the correct answer.

option c is the correct answer of the given

option C is the correct answer

Starvationis achieved by removal of the fuel burning in thefire. Any combustible material can be removed or gas or fuel flows shut off. Specificmethodsof extinguishingfiresoften involve a combination of more than one of the three principles.

We know that in order to freeze a liquid, we have to lower the temperature. As the temperature lowers, the solution becomes more ordered as it moves toward the solid phase. This is an effect that works against the second law of thermodynamics. In short, entropy (disorder) likes to increase not decrease in the natural scheme of things. So if we have to lower the temperature to a certain point to freeze a pure solvent, when we add a solute we add to the entropy of the system, The mixture is more disordered than the pure. This additional amount of entropy must now be overcome to allow the liquid to change phases into a solid (become ordered). This means that the temperature will have to be even lower than before. Thus addition of any type of solute to a solvent will lower its freezing point.