Explore topic-wise InterviewSolutions in .

A)1) Magnetization2. Fractional distillation3. Solvent extractionB. 1. because most of the gas escapes out.2. because co2 is filled with pressure in the bottle.C. 1. J.J. Thomson2. Lord Rutherford

1 is a roght ansure

A hydrocarbon is consist of C and H and empirical formula can be written as CxHy.To find the empirical formula, you have to find the moles of C and Hrelesed in form of H2O and CO2.18 g H2O contain 2 moles of H atoms⇒0.72 gram of H2O will contain = 2/18 x 0.72 = 0.08 moles of H​44 g of CO2contain 1 mole of C atom⇒3.08 gramof CO2 will contain 1/44 x 3.08 = 0.07 moles of C​Ratio of x and y = 0.07/0.08 = 7 : 8So the empirical formula will be: C7H8

Air is a mixture.

(i) Air can be separated into its constituents like oxygen, nitrogen etc. by the physical process of fractional distillation.

(ii) Air shows the properties of all the gases present in it.

(iii) Air has a variable composition.

(iv) Liquid air does not have a fixed boiling point.

Sulfur has been used for centuries to help treat acne and other skin conditions, due to its antimicrobial properties.

The acid value (AV) is a common parameter in the specification of fats and oils. It is defined as the weight of KOH in mg needed to neutralize the organic acids present in 1g of fat and it is a measure of the free fatty acids (FFA) present in the fat or oil.

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D-block elements occupy the space between the s-block and p-block in the periodic table. Since they bridge the two blocks and show a transition in the properties from the metals to the non-metals, they are also calledTransition elements.The valence electrons fills up the penultimate d-orbital energy level – according to the Aufbau principle, giving rise to four series of d-block elements – 3d, 4d, 5d and the 6d series. However 6d series is considered incomplete. In addition, as the criteria goes, the d-block elements Zinc, Cadmium and Mercury are not considered transition elements as they have completely filled d-orbitals in their ground and excited states.D-block elements show typical metallic behaviour. These are characterised by high tensile strength, malleability, ductility, electrical and thermal conductivity as well as metallic lustre.

these are transition elements

c)oxidising nature of H2O2In given reationoxidation number of Oxygen in H2O2 is -1 and it gain electrons and attains ON -2 it states H2O2itself reduces and oxidises H2S.

The d-block elements are found ingroups3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 of the periodic table;

d-block elements are also known as thetransition metals.

The d orbital is filled with the electronic shell “n-1.”

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thnx

On addition of conc. H2SO4 to a chloride salt, colourless fumes are evolvedbut in case of iodide salt, violet fumes come out. This is because

(i) H2SO4reduces HI to I2

(ii) HI is of violet colour

(iii) HI gets oxidised to I2

(iv) HI changes to HIO3

In qualitative analysis when H2S is passed through an aqueous solution ofsalt acidified with dil. HCl, a black precipitate is obtained. On boiling theprecipitate with dil. HNO3, it forms a solution of blue colour. Addition of excessof aqueous solution of ammonia to this solution gives _________.

(i) deep blue precipitate of Cu (OH)2

(ii) deep blue solution of [Cu (NH3)4]2+

(iii) deep blue solution of Cu(NO3)2

(iv) deep blue solution of Cu(OH)2.Cu(NO3)2

In a cyclotrimetaphosphoric acid molecule, how many single and doublebonds are present?

(i) 3 double bonds; 9 single bonds

(ii) 6 double bonds; 6 single bonds

(iii) 3 double bonds; 12 single bonds

(iv) Zero double bonds; 12 single bonds

Which of the following elements can be involved in pπ–dπ bonding?

(i) Carbon

(ii) Nitrogen

(iii) Phosphorus

(iv) Boron

Which of the following pairs of ions are isoelectronic and isostructural?

Affinity for hydrogen decreases in the group from fluorine to iodine. Which ofthe halogen acids should have highest bond dissociation enthalpy?

(i) HF

(ii) HCl

(iii) HBr

(iv) HI

Bond dissociation enthalpy of E—H (E = element) bonds is given below. Whichof the compounds will act as strongest reducing agent?

(i) NH3

(ii) PH3

(iii) AsH3

(iv) SbH3

On heating with concentrated NaOH solution in an inert atmosphere of CO2,white phosphorus gives a gas. Which of the following statement is incorrectabout the gas?

(i) It is highly poisonous and has smell like rotten fish.

(ii) It’s solution in water decomposes in the presence of light.

(iii) It is more basic than NH3.

(iv) It is less basic than NH3.

Which of the following acids forms three series of salts?

(i) H3PO2

(ii) H3BO3

(iii) H3PO4

(iv) H3PO3

Strong reducing behaviour of H3PO2is due to

(i) Low oxidation state of phosphorus

(ii) Presence of two –OH groups and one P–H bond

(iii) Presence of one –OH group and two P–H bonds

(iv) High electron gain enthalpy of phosphorus

On heating lead nitrate forms oxides of nitrogen and lead. The oxides formedare ______.

(i) N2O, PbO

(ii) NO2, PbO

(iii) NO, PbO

(iv) NO, PbO2

Which of the following elements does not show allotropy?

(i) Nitrogen

(ii) Bismuth

(iii) Antimony

(iv) Arsenic

Maximum covalency of nitrogen is ______________.

(i) 3

(ii) 5

(iii) 4

(iv) 6

Which of the following statements is wrong?

(i) Single N–N bond is stronger than the single P–P bond.

(ii) PH3can act as a ligand in the formation of coordination compoundwith transition elements.

(iii) NO2is paramagnetic in nature.

(iv) Covalency of nitrogen in N2O5is four.

A brown ring is formed in the ring test for NO3–ion. It is due to the formation of

(i) [Fe(H2O)5(NO)]2+

(ii) FeSO4.NO2

(iii) [Fe(H2O)4(NO)2]2+

(iv) FeSO4.HNO3

Elements of group-15 form compounds in +5 oxidation state. However,bismuth forms only one well characterised compound in +5 oxidation state.The compound is

(i) Bi2O5

(ii) BiF5

(iii) BiCl5

(iv) Bi2S5

On heating ammonium dichromate and barium azide separately we get

(i) N2in both cases

(ii) N2with ammonium dichromate and NO with barium azide

(iii) N2O with ammonium dichromate and N2with barium azide

(iv) N2O with ammonium dichromate and NO2with barium azide

In the preparation of HNO3, we get NO gas by catalytic oxidation of ammonia.The moles of NO produced by the oxidation of two moles of NH3will be ______.

(i) 2

(ii) 3

(iii) 4

(iv) 6

The oxidation state of central atom in the anion of compound NaH2PO2willbe ______.

(i) +3

(ii) +5

(iii) +1

(iv) –3

Which of the following is not tetrahedral in shape?

(i) NH4+

(ii) SiCl4

(iii) SF4

(iv) SO42–

Which of the following are per oxoacids of sulphur?

(i) H2SO5and H2S2O8

(ii) H2SO5and H2S2O7

(iii) H2S2O7and H2S2O8

(iv) H2S2O6and H2S2O7

The last electron in the electronic configuration enters the p-orbital of the p-block elements.Elements in Groups 13-18 of the Periodic Table are called P-block elements.These include metals, metalloids, noble gases and halogens. Some of the commonly known elements in the P-block are:

Metals: Aluminium (Al), Boron (B), Tin (Sn).

Metalloids:Silicon (Si), Germanium (Ge)

NobleGases: Helium (He), Neon (Ne), Argon (Ar).

Halogens: Fluorine (F), Chlorine (Cl), Bromine (Br).Consequently, there are six groups of p-block elements in the periodic table numbering from13 to 18.

First group: group IIIA called asBoron group

Second group: group IVA called asCarbon group.

Third group: group VA called asNitrogen group.

Fourth group: group VIA called asChalcogens.

Fifth group: group VIIA called asHalogens.

Sixth group: zero group or group 18 called asInertorNoble gasses group.

Elements having a place within thegroup 13 (i.e. group IIIA) to group 17 (i.e. group VIIA)of the periodic table alongside thegroup 18 i.e. the zero groupelements together frame the p-block of the periodic table.

Compound B is NaOHSodium hydroxide (NaOH) is a commonly used base and it absorbs moisture from the atmosphere and becomes sticky.

The acidic oxides react with base to give salt and water. Lets take an acidic oxide - Sulphur dioxide.The reaction between NaOH and SO2 can be given as

2NaOH + SO2 -------> Na2SO3 + H2O

4) all alkanes exhibit isomerism is the answer for the question because in order to exhibit isomerism alkanes should have minimum of 3 - 4 carbon atoms. Ethane, methane will not exhibit any isomerism. Therefore 4) is the answer

both nonmetal and metalloid

group 18 is exception so argon is bigger than sodium

aawart=7 warg=18, this modern periodik table

this is the modern periodic tabel

This is a Modern Periodic table which in 18 Horizontal and 8 Vertical group

this is mordern periodic table

what is the question we know this is periodic table sis

This is the modern periodic table

This is the modern periodic table. Theperiodic table, also known as theperiodic table of elements, is a tabular display of thechemical elements, which are arranged byatomic number,electron configuration, and recurringchemical properties. The structure of the table showsperiodic trends. The seven rows of the table, calledperiods, generally havemetalson the left andnon-metalson the right. The columns, calledgroups, contain elements with similar chemical behaviours. Six groups have accepted names as well as assigned numbers: for example, group 17 elements are thehalogens; and group 18 are thenoble gases. Also displayed are four simple rectangular areas orblocksassociated with the filling of differentatomic orbitals.

The elements from atomic numbers 1 (hydrogen) through 118 (oganesson) have been discovered or synthesized, completing seven full rows of the periodic table. The first 94 elements all occur naturally, though some are found only in trace amounts and a few were discovered in nature only after having first been synthesized. Elements 95 to 118 have only been synthesized in laboratories ornuclear reactors. The synthesis of elements having higher atomic numbers is currently being pursued: these elements would begin aneighth row, and theoretical work has been done to suggest possible candidates for this extension. Numerous syntheticradionuclidesof naturally occurring elements have also been produced in laboratories.

The organization of the periodic table can be used to derive relationships between the various element properties, and also to predict chemical properties and behaviours of undiscovered or newly synthesized elements. Russian chemistDmitri Mendeleevpublished the first recognizable periodic table in 1869, developed mainly to illustrate periodic trends of the then-known elements. He also predicted some properties ofunidentified elementsthat were expected to fill gaps within the table. Most of his forecasts proved to be correct. Mendeleev's idea has been slowly expanded and refined with thediscovery or synthesis of further new elementsand the development of new theoretical models to explain chemical behaviour. The modern periodic table now provides a useful framework for analyzingchemical reactions, and continues to be widely used inchemistry,nuclear physicsand other sciences.

Theperiodic table, also known as theperiodic table of elements, is a tabular display of thechemical elements, which are arranged byatomic number,electron configuration, and recurringchemical properties. The structure of the table showsperiodic trends. The seven rows of the table, calledperiods, generally havemetalson the left andnon-metalson the right. The columns, calledgroups, contain elements with similar chemical behaviours. Six groups have accepted names as well as assigned numbers: for example, group 17 elements are thehalogens; and group 18 are thenoble gases. Also displayed are four simple rectangular areas orblocksassociated with the filling of differentatomic orbitals.

The elements from atomic numbers 1 (hydrogen) through 118 (oganesson) have been discovered or synthesized, completing seven full rows of the periodic table.[1][2]The first 94 elements all occur naturally, though some are found only in trace amounts and a few were discovered in nature only after having first been synthesized.[n 1]Elements 95 to 118 have only been synthesized in laboratories ornuclear reactors.[3]The synthesis of elements having higher atomic numbers is currently being pursued: these elements would begin aneighth row, and theoretical work has been done to suggest possible candidates for this extension. Numerous syntheticradionuclidesof naturally occurring elements have also been produced in laboratories.

The organization of the periodic table can be used to derive relationships between the various element properties, and also to predict chemical properties and behaviours of undiscovered or newly synthesized elements. Russian chemistDmitri Mendeleevpublished the first recognizable periodic table in 1869, developed mainly to illustrate periodic trends of the then-known elements. He also predicted some properties ofunidentified elementsthat were expected to fill gaps within the table. Most of his forecasts proved to be correct. Mendeleev's idea has been slowly expanded and refined with thediscovery or synthesis of further new elementsand the development of new theoretical models to explain chemical behaviour. The modern periodic table now provides a useful framework for analyzingchemical reactions, and continues to be widely used inchemistry,nuclear physicsand other sciences.

they are called metalloids because they show some properties of metals and some properties of non metal

Ans :- 1. On the basis of electronic configuration of elements, the periodic table is divided into four blocks namely, s-block, p-block, d-block and f-block.

2. The elements of s-block (except hydrogen), d-block and f-block are all metals.

3. In the p-block, all the three types of elements, i.e metals, non-metals and metalloids are present.

4. A zig-zag line separates the metals on the left side form the non-metals on the right side of the periodic table.

5. The bordering elements along the zig-zag line are the metalloids. These are Antimony (Sb), Germanium (Ge), Boron (B), Silicon (Si), Arsenic (As), Tellurium (Te), Polonium (Po). They show intermediate properties and are called as metalloids or semi-metals.

We know,

∆E=hc/λ

So,

λ~1∆E

Hence, the wavelength of spectral line for an electronic transition is inversely related to the difference in the energy levels involved in the transition.

The lanthanide or lanthanoid series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57 through 71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare earth elements.Theyarecalledthe "innertransition metals." Thetransition elementsare unique in thattheycan have an incomplete inner subshell allowing valence electrons in a shell other than the outer shell. Otherelementsonly have valence electrons in their outer shell.

The products of hydrolysis are XeOF4and XeO2F2where the oxidation states of all the elements remain the same as it was in the reacting state.XeF6+ H2O --->XeOF4+2HFXeO+ H2O ---> XeO2F2+2HFXeO2F2+ H2O----> XeO3+2HF Thus oxidation state is same +6Hence the XeF6does not show redox reaction

Zinc is not consider as a transition metal because its compounds or ions (Zn2+) contain a full filled d-orbital or sub shell and are unstable.Moreover it have only one ion which is the (Zn2+). Hence zinc do not form colored aqueous ions because it do not have at least one vacant d-orbital in which it can receive an electron in a reaction.

Considering Zinc not as a transition metal require you to understand and see into consideration the properties of transition metals . You can start with their ability to have variable oxidation state and their catalytic nature in reactions.

i. Actually the ionic radius tends to decrease for metals (including transition metals) with increasing atomic number as they lose electrons, in other words as they lose there outer shell electron but for the non metals the ionic radius increases with increasing atomic number as they gain electrons but since they only increase with a very very small amount, it can be considered as negligible. So therefore we can conclude by saying that the overall trend of the ionic radius is decreasing across a period.

ii.Transition elements have tendency to formcomplexesmore than s and p block elements, which form only a few complexes.

The reason is :-

They have small , highly charged ions.

They have vacant low energy orbitals to accept lone pairs of electrons donated by other groups or ligand .

So they are able to form complexes with the groups which are able to donate an electron pair . These groups are known asligands.

iii. Transition metals show catalytic behavior mainly due to the following reasons: The presence of vacant d orbitals. They have the ability to exhibit variable valencies. They have a tendency to form complex compounds.

option 3 is the right answer

option 3 is correct of this problem

yes, option 3 is the correct Answer.

because in presence of air magnesium ribbon reacts with oxygen and forms a layer of magnesium oxide on it

Magnesium ribbon is cleaned before burning it in air in order to remove oxide layer, presence of which slowdowns the oxidation process. So, by cleaning it, the burning process takes place easily

it doesn't match with options given in question

NaOH + H2So4 = Na2So4 + H2O

Balanced equation:-

2 NaOH + H2So4 = Na2So4 + 2 H2O

Reaction type:-

Double replacement

option b

We will use gas law as

P1V1 +P2V2 = PfVf ..... ( Vf = V1+V2)

=> 5*9+10*6 = Pf(10+5)=> 45+60 = Pf(15)=> Pf = 105/15 = 7atm

option 2

It is defined as the mathematical product of the separation of the ends of a dipole and the magnitude of the charges. A dipole moment is simply the measure of net polarity in a molecule.

A dipole moment is a measurement of the separation of two opposite electrical charges. Dipole moments are a vector quantity. The magnitude is equal to the charge multiplied by the distance between the charges and the direction is from negative charge to positive charge: μ = q · r.The SI unit for electric dipole moment is thecoulomb-meter. This is too large to be practical on the molecular scale. Bond dipole moments are commonly measured in debyes, represented by the symbol D, which is obtained by measuring the charge in units of 10−10statcoulomb and the distance d in Angstroms.

For a first order reaction

T= 1/k ×ln(Ao/At)

Where Ao is initial concentration ,At is concentration at time t and k is rate constant.

So your answer is ln10/6 = 0.384 mins

Hence, option (a) is correct.

6000Å = 6000^-10m = 6.0^-7m

From Planck's equation .. each photon has energy, E = hc/λ (J)

If N photons are emitted per sec ..Total emission power, P = N(s⁻¹) x E(J) = NE (J/s) = 25 W

25 = NE = N x hc/λN = 25λ / hc .. 25 x 6.0^-7 / (6.625^-34 x 3.0^8) .. .. ►N = 7.55^19 photons per sec

option (c) is correct.

1 hogaa.

The atomic number of chlorine is 17. Its electronic configuration is 1s22s22p63s23p5or [Ar]3s23p5. It contains a single unpaired electron in the 3p orbital. Thus, the electron in the 3p orbital will have the following set of four quantum numbers

1) principal quantum number, n = 3

2) Azimuthal quantum number, l = 1

therfore the number of unpaired electrons of chlorine=4

Ans :- Postulate – I

A straight line segment can be formed by joining any two points in space.

In Geometry, a line segment is a part of a line that is bounded by 2 distinct points on either end. It consists of a series of points bounded by the two endpoints. Thus a line segment is measurable as the distance between the two endpoints. A line segment is named afterthe two endpoints with an overbar on them.

Postulate – II

Any straight line can be extended indefinitely on both sides. Unlike a line segment, a line is not bounded by any endpoint and so can be extended indefinitely in either direction. A line is uniquely defined as passing through two points which are used to name it.

Postulate – III

A circle can be drawn with any centre and any radius. For any line segment, a circle can be drawn with its centre at one endpoint and the radius of the circle as the length of the line segment. Consider a line segment bounded by two points. If one of these points is taken as the centre of a circle and the radius of the circle is taken as equal to the length of the segment, a circle canbe drawn with its diameter twice than the length of the line segment.

In the above example, the line segment AO serves as the radius of a circle with centre at point O and a diameter equal to AB wherel(AB) =2l(AO).

Postulate – IV

All right angles are congruent or equal to one another. A right angle is an angle measuring 90 degrees. So, irrespective of the length of a right angle or its orientation all right angles are identical in form and coincide exactly when placed one on top of the other.

A right angle

Postulate – V

Two lines are parallel to each other if they intersect the third line and the interior angle between them is 180 degrees.

'Parallel lines’ are a set of 2 or more lines that never cross or intersect each other at any point in space if they are extended indefinitely. As you can see in the above image, line 1 and line 2 are parallel if and only if the sum of angles ‘a’ and ‘b’ they make with thetransversal is 180 degrees.

Postulates of Quantum Theory. ... Note 1: As a consequence ofPostulate4, we will see that represents the probability of finding the system between and at time . : Any observable (i.e., any measurable property of the system) can be described by an operator. The operator must be linear and hermitian.

Powder coating can be used as both a protective and decorative finish, with an almost unlimited range of colors and textures available.

We know that opposite charges attract each other. So we give the substance positive charge and the spray negative charge, so that due to electrostatic attraction the spray forms a uniform layer over the substance

concentrated sulphuric acid will react vigorously and cause burns

wrong

2Mg+O2-2MgOMgO+H2O-Mg(OH)2CuSO4+Fe-FeSO4+Cu

(a). 2Mg(s) + O2(g) ----> 2MgO(s)(b). Mgo(s) + H2O (l) -----> Mg(OH)2(c). CuSO4 (aq) + Fe(s) -------> FeSO4 (aq) + Cu(s)

Magnesium is a reactive metal, it steals oxygen from metal oxides like copper oxide except for more reactive metals.

Mg + CuO → MgO + Cu

Copper(II)oxide, CuO, will be converted to metalliccopperwhen it is heated withhydrogen. This reaction is a typical redox reaction (oxidation-reduction).Hydrogenreduces theoxideof the less reactive metal to free metal.