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A.(a)88.8B.(c)Na2S,NaFC.(a)-40

Ans :- Generally, If valence shell contains 1 to 3 electrons are most electromotive and lose electrons and form positive ions. So, they form ionic compounds.

If valence shell contains 4-7 electrons, they generally try to form covalent bond by sharing of electrons. If they contain 7 electrons in outermost shell, single bond is formed as in Cl2. If they contain 6 electrons in outermost shell, double bonds are formed as in O2. If they contain 5 electrons in outermost shell, triple bonds are formed as in N2.

If they contain 7 electrons in outermost shell, gain of one electron makes it negative ion. So, it can form ionic bond with the cation also as NaCl.

Acetylene (ethyne) C2H2, has a triple bond between the two C atoms which consist of one sigma bond and two pi bonds. Both of the C-H bonds are sigma bonds. That would make a total of3sigma + 2 pi bonds.

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Sigma bond: This type of covalent bond is formed by theaxial or end to end overlappingof half filled atomic orbitals of the atoms participating in bonding. The electron cloud formed as a result of axial overlap is cylindrically symmetrical about inter nuclear axis.

Pi bond: This type of bond is formed by lateral or side wise overlap of the half filled atomic orbitals of the atoms participating in bonding. The pi bond consists of two charged clods above and below the plane of the atoms involved in bond formation.

Methane organizes itself into a tetrahedral shape, with the carbon atom in the middle and the 4 hydrogen atoms equi-distributed, so to speak, around it. Knowing this*, we can reason that the displacements from the carbon atom to the 4 hydrogen atoms sum to zero, and thus, considering one of these displacements as 1 unit straight up, we find that the equal vertical component of the other 3 displacements must be 1/3 units down. Thus, the bond angle will be the arccosine of -1/3, which comes out to a hair over 109 degrees and 28 minutes, as you note

option c

option C is the correct answer

Ch4- C2H6- C3H8- C4H10- C5H12

1,2 and 5 go addition reaction

C2H6, C3H8 and CH4 are undergo in addition reaction.

saturated hydrocarbon have the formula .. CnH2n+2

so, C4H10 , C6H14

Mass (solute) = 40 gramMass (solvent) = 320 gramMass (solution) = Mass (solute) + Mass (solvent) = 40 gram + 320 gram = 360 gram∴ Mass % (solution) = [ Mass (solute)/Mass (solvent)]× 100 = [40/360]× 100 = 11.1 %

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A desert cooler cools better on a hot dry day because on a hot dry day temperature is high and humidity is less which helps in better cooling . Due to higher rate of evaporation it gives better cooling effect

1. Adesert coolercoolsbetter on a hotdry day because on ahotdry day temperature is high and humidity is less which helps inbetterevaporation. Due to the higher rate of evaporation it givesbetter coolingeffect.

2. In anearthen pot,watergets evaporated quickly through the pores. Cooling is caused by evaporation. Some heat energy is utilised during the process of evaporation. Since this energy is taken from thewateritself, it leads to a lowering of temperature in the remaining amount ofwater.

On a hot dry day ,the temperature is high and humidity is low. The rate of evaporation increases with increase in temperature and decrease in humidity. A desert cooler functions on the principle of evaporation. The water takes heat from the hot desert cooler and evaporates. The evaporation of water cools the pads and the circulating water. As a result, the incoming air also gets cooled down

Answer: Adesert coolercoolsbetter on a hot dry daybecause on ahot dry daytemperature is high and humidity is less which helps inbetterevaporation. Due to the higher rate of evaporation it givesbetter coolingeffect.

Discovery of the Neutron (1932) The story begins in 1932, with the discovery of the neutron by Sir James Chadwick, an English physicist. Until 1932, the atom was known to consist of a positively charged nucleus surrounded by enough negatively charged electrons to make the atom electrically neutral.

Orbit- It is a well defined circular path in which the electrons are supposed to move in bohr's model.Orbital- Its a 3D region in the space around the nucleus in which the probablity of finding an electron is maximum.Orbital- Except sorbital, all otherorbitalsare directional.

Distance between two orbital, we can assume here as radial distanceRadius of 3 rd orbit=(0.529x3^2)/2Radius of 4th orbit=(0.529x4^2)/2Distance between 4th and 3rd Bohr orbits of He+ is1.851 × 10–10m

It is because the molecules ofhoneyis closerthan waterto each other hencehoneyhasmorestrong intermolecular attractive forcesthan water,so the particles are strongly binded inhoney than water,that is whyhoney is more viscous than water.

(a) is the correct answer

In chemistry, alone pairrefers to apairof valenceelectronsthat are not shared with another atom and is sometimes called a non-bondingpair.Lone pairsare found in the outermostelectronshell of atoms. They can be identified by using a Lewis structure.

hence XeF6

The given data: P1 =1atm; V1 = 1L; P2 =0.75atm; V2 =1l; w1 =2 g; w1=1g; T1 = 300K; T2 =?

We know that, P1V1/T1 = P2V2/T2 or

P1V1/P2V2 = n1RT1/n2RT2 = w1RT1/w2RT2

Therefore, P1V1/P2V2 = w1RT1/w2RT2

1x1/0.75x1 = 2x 300/1xT2

T2 = 2x300x0.75

T2 = 450 K

thanks

the right answer is 3)6.29g

Magnesium ribbon mustbecleaned before burning in airso that the the layer ofmagnesiumoxide (which is formed due to reaction ofmagnesiumwithair) can be removed in order to get the desired chemical reaction.

As per given reactions:In first reaction copper replaces silver as copper is more reactive than silver, in second reaction lead replaces copper as lead is more reactive than lead and in third reaction zinc replaces lead as zinc is more reactive than lead.

Therefore, from given metals zinc is most reactive of all metals

(D) is correct option

If 1 mole is equal to 2*10^24 , there will be no change in the mass of any atom because, one mole of a substance is equal to its atomic mass if the substance is atomic therefore 1 mole of C atom= 12 amu . option C

please explain it more

explained above , see the correct answer

A catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction. A catalyst will appear in the steps of a reaction mechanism, but it will not appear in the overall chemical reaction (as it is not a reactant or product). Generally, catalysts alter the mechanism of the reaction in a substantial way such that the new barriers along the reaction coordinate are significantly lower. By lowering the activation energy, the rate constant is greatly increased (at the same temperature) relative to the uncatalyzed reaction.

PbS + 4H2O2→PbSO4+ 4H2O

A colloid is a heterogeneous mixture whose particles are not as small as solution but they are so small that cannot be seen by naked eye. When a beam of light is passed through a colloid then the path of the light becomes visible. For example milk, smoke etc.

Properties1. A colloid is a heterogeneous mixture.2. The size of particles of a colloid is too small to be individually seen by naked eyes.3. Colloids are big enough to scatter a beam of light passing through it and make its path visible.4. They do not settle down when left undisturbed, that is, a colloid is quite stable.5. They cannot be separated from the mixture by the process of filtration. But, a special technique of separation known as centrifugation can be used to separate the colloidal particles.

The number of entities in a mole is given by the Avogadro constant, NA , which is approximately6.022×10^23 entities per mol. For CO2 the entity is a molecule made up of3 atoms. Thus in 2 moles we have around, 2mol×6.022×10^23 molecules mol−1 , which is 1.2044×10^24 molecules

10FeC2O4+ 6KMnO4+ 24H2SO4----> 3K2SO4+ 6MnSO4+ 5Fe2(SO4)3+ 24H2O +20CO2

So we see that

6 moles of KMnO4is required to oxidize 10 moles of FeC2O4

Then, 1 mole of FeC2O4would be oxidized by = ?

6/10=0.6