2599 + Interview Questions in Chemistry in Class 9 Page 29 InterviewSolution

1401.	In isotopes of an element, the number of ........ Differes.
Answer» ANSWER :NEUTRON

Discussion

1402.	In isobars, the number of .... is samne.
Answer» PROTON and ELECTRON proton and NEUTRON electron and neutron NEUTRONS ANSWER :A::D

Discussion

1403.	In industries, chlorine is used in the manufacture of hydrogen chloride. Explain.
Answer» SOLUTION :N/A

Discussion

1404.	In emulsion, dispersing medium is liquid whiledispersed phase is _____ .
Answer» ANSWER :LIQUID

Discussion

1405.	In electroplating process the metal to be caoted is taekn as ________.
Answer» SOLUTION :N/A

Discussion

1406.	In Dobereiner's traids, the atomic weight of the middle element in the ………….of the atomic masses of 1st and 3rd elements.
Answer» ANSWER :AVERAGE

Discussion

1407.	In doberiener 's classification the atomic weight and the properties of the first element are almost equal to theaverage of those of the 2nd and 3rd elements of a triad
Answer» ANSWER :FALSE

Discussion

1408.	In Darjeeling, distilled water boils at a temperature
Answer» above 373 K above 473 K below 373 K at 373 K Solution :PRESSURE decreases with increase in altiude, andhence,boilingpiont decrease. SinceDarjeelingis at higherattidues, WATER boils 373k K, i.e., below `100^(@)C`.

Discussion

1409.	In cold countries, ethylene glycol is used car radiators for both winter as well as summer seasons. Explain.
Answer» Solution :(i) boiling point of ethylene glycol (ii) changes OBSERVED in the radiator of a car during summerand WINTER (iii) effect ADDITION of ethylene glycol to WATER of a radiator

Discussion

1410.	In chlorine. argon, potassium and calcium, the number of electrons are 17, 18. 19, 20 and number of neutrons are 18, 22. 20, 20 respectively. Whlch pair of elements is isobars?
Answer» CHLORINE and calcium Potassium and chlorine ARGON and calcium Potassium and argon ANSWER :A::C::D

Discussion

1411.	In aqueous solution, sodium sulphate (Na_(2)SO_(4)) dissociates into ions as follows . Na_(2)SO_(4)(aq) to 2Na^(+) (aq)+SO_(4)^(2-)(aq) Calculatethe number of ions produced when 23.75 g of sodium sulphateis dissolved in water .
Answer» ANSWER :`3.017xx10^(23)`

Discussion

1412.	Inan unsaturated solution more solute can be dissolved without increasingthe amount of the …………
Answer» ANSWER :SOLVENT

Discussion

1413.	In an organic chemistery laboratory a scientist subjecteda hydrocarbon to combustion The products occupied a volume ratio of 4:3 under the same conditions of temperature and pressure .The scientist drew the possible structures of the hydrocarbon. She then subjected the compound to ozonolysis to identify the exact structure. Predict the products formed when the compound is treated with bro-mine water.
Answer» Solution :GENERAL combustion equation is `C_xH_y+(x+y/4)O_2rarrxx.CO_2+y/2H_2C` As the molar RATIO of `CO_2` and `H_2O` is 4:3 x=4 and `y/2=3rArry=6` `thereforeX=C_4H_6` Since it reacts With bromine water and its formula INDICATES that X is butyne `therefore` X may be 1-Butyne or 2- Butyne

Discussion

1414.	In an orbit 32 electrons can be accomodated, then it will be ....... Orbit.(L, M, N)
Answer» ANSWER :N

Discussion

1415.	In an experiment to verifty the law of conservation of mass ina chemical reaction four studetns A,B,C and D noted down the following observation for the different in the mass of apparatus before and after the chemical reation, A-4g,B-8g,C-zero g,D-10 g Which student has made the correct observation and why?
Answer» Solution :Student C has madethe CORRECT observation SINCE according to the law there is no change in mass of reactants and products taking PART in a chemicla REACTION

Discussion

1416.	In an atom, the mass number of an atom is equal to the number of ____.
Answer» nucleons protons ELECTRONS Neutrons Answer :A

Discussion

1417.	In an atom, electrons revolve around the uncleus in fixed orbits.
Answer» ANSWER :1

Discussion

1418.	In air, _____ is a solvent.
Answer» ANSWER :NITROGEN

Discussion

1419.	In Aerosol the dispersed phase is liquid and the dispersion medium is gas.
Answer» SOLUTION :CORRECT statement: In AEROSOL, The DISPERSED phase is solid and the dispersion medium is gas.

Discussion

1420.	In a reaction, 5.3 g of sodium carbonate reacted with 6g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g of water and 8.2 g of sodium ethanoate. Show that these observations are in agreement with the law of conservation of mass. underset("carbonate")("Sodium") + underset("acid")("Ethanoic") to underset("ethanoate")("Sodium")+ "Water" +underset("dioxide")("Carbon")
Answer» Solution :`UNDERSET("CARBONATE")("SODIUM") + underset("ACID")("Ethanoic") to underset("ethanoate")("Sodium")+ "Water" +underset("dioxide")("Carbon")` `5.3 g + 6 g to 8.2 g+0.9 g + 2.2 g` `11.3 g to 11.3 g` i.e., L.H.S. = R.H.S. `:.` mass of reactants = mass of product This shows that the observations are in agreement with the LAW of conservation of mass.

Discussion

1421.	In a reaction, 5.3 g of sodium carbonate reacted with 6 g of acetic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium acetate. Show that these observations are in agreement with the law of conservation of mass. sodium carbonate + acetic acid→sodium acetate + carbon dioxide + water
Answer» Solution :The chemical reaction LEADING to PRODUCTS is `"SODIUM carbonate"+"ethanoic acid" to "sodium ethanoate"+"carbon dioxide"+" water"`. `"MASS of reactants" = (5:3+60)=11:3 g` `"Mass of products"= (8:2 + 2:2 +0.9) 11:3g`. The reactants and products have same mass. This means that there was no loss of mass during the reaction. Therefore, the data is in AGREEMENT with law of conservation of mass

Discussion

1422.	In a reaction 5.3g of sodium carbonate reacted with 6g of ethanoic acid. The products where 2.2g of CO., 0.9g water and 8.2g of sodium ethanoate show that these observations are in agrrengment with the law of conservation of mass. Sodium carbonate+ ethanoic acid Sodium ethanoate + carbondioxide + water
Answer» Solution :Sodium CARBONATE + ethanoic ACID `to` Sodium ethanoate + carbon DIOXIDE + water REACTION [Mass of Reactant] `5.3 + 6.0 = 11.3` gm Mass of PRODUCTS`2.2 + 0.9 + 8.2 = 11.3 ` gm `therefore` Mass of Reactants = Mass of products

Discussion

1423.	In a mixtureof chloroform and water , chloroform forms the .............. layers.
Answer» ANSWER :LOWER

Discussion

1424.	In a hypothetical reaction X to Y, the activation energies of the forward and backward reactions are 13 kj/mole and 7 kj/mole, respectively. Calculate heat of the reaction.
Answer» Solution :(i) RELATION between `Delta H, E_(a) " and" E_(B)` (ii) calculation of heat of reaction from the GIVEN `E_(a) " and" E_(b)` values (iii) 6 kJ/mole

Discussion

1425.	in a heterogeneous mixture , the constituents have no clear boundaries of separation.
Answer» ANSWER :F

Discussion

1426.	In a dam , the surface water is at higher temperature than the water deep within the dam .
Answer» ANSWER :T

Discussion

1427.	In a compound , the constituent elements are present in a fixed ratio by mass. This statement is called the law of ....................
Answer» SOLUTION :CONSTANT PROPORTIONS

Discussion

1428.	In achemistry lab, Rina took some mercury and water in two test tubes separately. Then she drained off both the liquids and on observing the emty test tubes, found some difference. Can you guess what the difference is ? Explainwith appropriatereasons.
Answer» Solution :Water droplets are found on the INNER surface of one test tube while the other test tube is completely dry. In the CASE of water, ADHESIVE forces are more than cohesive forces but in case of mercury cohesive forcesare more than ahesive forces. Due to stronger adhesive force, water droplets STICK to the test tube.

Discussion

1429.	In a chemical compound , the constituent elements are present in …………. Proportions by weight .
Answer» ANSWER :FIXED

Discussion

1430.	In a certain reaction 2A + B hArr 4C, the concentration of A decreases from 5 xx 10^(-3) " mol"//L to 2 xx10^(-3) " mol"//L in 30 s. What is the rate with respect to C ?
Answer» `5XX10^(-5) " mole " L^(-1)s^(-1)` `5xx10^(-5) L^(-1) " mole"^(-1) s^(-1)` `21 xx10^(-4) " mole" L^(-1)s^(-1)` `2 xx 10^(-4) L^(-1) " mole"^(-1) s^(-1)` Solution :The rate of reaction with respect to `A=("Change in concentration")/("TIME")` `(d[A])/(dt)=(5xx10^(-3)-2xx10^(-3))/(30)=(3xx10^(-3))/(30)` `=1xx10^(-4) " mol" // "lit's` reaction is `2A+B to 4C` `(1)/(2)(d[A])/(dt)=(1)/(4)(d[C])/(dt)` The rate of reaction in terms of 'C' is `(Delta[C])/(Delta t)=(4)/(2)xx(Delta[A])/(Delta t)` `=2xx(d[A])/(dt)=2xx1xx10^(-4)=2xx10^(-4) " mole " // L^(-1)` .SEC

Discussion

1431.	In a canal ray experiment, different gases were found to produce canal rays with the same specific charge. Explain.
Answer» SOLUTION :(i) FACTORS AFFECTING SPECIFIC CHARGE (ii) Conditions where dfferent gases can have the same specific charge.

Discussion

1432.	In ""_(47)^(108)Ag, state the number of protons, neutrons and electrons respectively.
Answer» 47, 47, 61 47, 61 , 47 61,47,47 61,61,47 Answer :A::D

Discussion

1433.	In ""^(16)O_(8) the number 16 stands for
Answer» ATOMIC MASS Atomic NUMBER Atomic mass scale Number of ELECTRONS. ANSWER :A

Discussion

1434.	If Z = 3, what would be the valency of the element ? Also, name the element.
Answer» SOLUTION :By Z = 3, we mean that the atomic number of the ELEMENT is 3, its electronic configuration is 2,1. HENCE the valency of the element is 1 (Since the outermost shell has only one electron). Therefore, the element with Z = 3 is LITHIUM.

Discussion

1435.	If ._x^yA^(+1) or ._(x-1)^(y-1)B^(+1) were to be used instead of alpha-particles in Rutherford's experiment, which would be better and why ?
Answer» SOLUTION :(i) the factros affecting ANGLE of deflection (ii) the characteristics in which the TWO PARTICLES DIFFER.

Discussion

1436.	If we keep a box of ice creasm in a freezer for too long, crystals of ice are formedinside the box. Give reasons.
Answer» Solution :DUE to very low temperature in the freezer, the WATER vapour gets deposited as CRYSTALS of ice. Therfore, we get crytals of ice inside the box if KEPT in freezer for longer time.

Discussion

1437.	If we consider each student in chain as a particle of matter, then in which group do the particles hold each other with the maximum force?
Answer» SOLUTION :In the first GROUP, the particles hold each other with the MAXIMUM force.

Discussion

1438.	If we burn graphite
Answer» RESIDUE will be LEFT No residue will be left It will not burn It will change into diamond Answer :B

Discussion

1439.	If Thomson's model is considered to be correct, what would be the obervation of Ruterford's alpha-ray scattering experiment?
Answer» SOLUTION :If Thomson's model is correct, all the `alpha`-particles WOULD have penturate the gold FOIL and their angle of DEFLECTION would be insignificant.

Discussion

1440.	If there are x atoms in 32 g sulphur, then how many atoms will be there in 32 g oxygen in terms of x?
Answer» `(X)/(2)` 2x x 4x Solution :Mole of SULPHUR = `(32)/(32)` = 1 mole = x atoms Mole of OXYGEN = `(32)/(16)` = 2 mole = `2 XX x` atoms = 2x atoms

Discussion

1441.	If there are x atoms in 18 g carbon, then how many atoms will be there in 12 g magnesium ?
Answer» x 2x `(x)/(2)` `(x)/(3)` SOLUTION :MOLE of C = `(18)/(12)` = 1.5 mole = x atoms Mole of Mg = `(12)/(24)` = 0.5 mole = `(0.5)/(1.5) x =(x)/(3)`

Discussion

1442.	If the three elements X,Y and Z form a triad and atomic weights of X and Z are 9 and 40 respectively then the atomic weight of an element y is _________
Answer» ANSWER :24.5

Discussion

1443.	If the temperature of an object is 268 K, it will be equivalent to :
Answer» `- 5^(@)C` `+ 5^(@)C` `368^(@)C` `- 25^(@)C` ANSWER :A

Discussion

1444.	If the number of electrons in an atom is 8 and the number of protons is also 8, then (i) What is the atomic number of the atom? and (ii) What is the charge on the atom?
Answer» SOLUTION :(i) Atomic NUMBER = number of protons = 8. (11) Number of ELECTRONS = number of protons `therefore`the negative and positive CHARGES nullify each other. `therefore` the charge on the atom = 0 i.e. the atom is electrically neutral.

Discussion

1445.	If number of electrons in an atom is 8 and number of protons is also 8, then (i) what is the atomic number of the atom? and (ii) what is the charge on theatoms ?
Answer» SOLUTION :(i) Atomic numbr (Z) of the atom = No of protons = No of electons =8 Charge on the atom = No charge ACTUALLY when the number of protons and ELECTRONS are the same the atom is neutral .

Discussion

1446.	If K and L shells of an atom are full, then what would be the total number of electrons in the atom?
Answer» SOLUTION :MAXIMUM no of electrons in K-shell =2 Maximum no of electrons in L-shell =8 Total no of electrons in the ATOM =2+8=10

Discussion

1447.	If the energy difference between the orbits when an electron in H atom excited to higher energy orbit from its ground state is 12.1eV// atom , calcualte the frequency of radiation emitted (1 eV =1.602xx10^(-19J)) when electron comes back to second energy level.
Answer» Solution :(i) RELATION between energy and n (ii) CALCULATION of `n_2` value from the difference in energy. (iii) calculation of FREQUECNY from energy (iv) calculation of energy difference BASED on n values (V) calcualtion of frequency (vi) `v=0.456xx10^(15)s^(-1)`

Discussion

1448.	If the atomic number of some elemetns in the modern periodic table are 8,7,11,12,13 and 9 what type of ions do they form? Arrange the ions in the increasing order of their size and justify
Answer» Solution :(i) identification of the number of valece electrons in eahc element (ii) tendency of an atom of an element to lose or gain based on numbr of VALENCE electrons (iii) TYPE of ions formed (iv) variation of SIZE of an ion with charge

Discussion

1449.	If the atomic number of some element in the modern periodioc table are8,7,11,12,13 and 9 what type of ions do they form ? Arrange the ions in the increasing order of their size and justify
Answer» Solution :The elements with atomic number 8,7,11,12,13 and 9 are OXYGEN nitrogen sodium magnesium aluminumum and fluoringe respectively .These elements belons to VIA (16),VA(15),IA(1),IIA(2),IIIA(13)and VIIA(17)groups .generally these elements form `O^(-2),N^(-3),Na^(+),Mg^(+2),AI^(3+)` and `F^(-)` ions The order of ionic size is `Z^(-3)GTO^(-2)gtF^(-)gtNa^(+)gtMg^(+2)gtAI^(3+)`

Discussion

1450.	If the activation energy of forward reaction is four times the amount of energy released (DeltaH= -10 kcal), what could be the activation energy of the backward reaction ?
Answer» 50 kcal 60 kcal 40 kcal 30 kcal Answer :A

Discussion

Explore topic-wise InterviewSolutions in .

In isotopes of an element, the number of ........ Differes.

In isobars, the number of .... is samne.

In industries, chlorine is used in the manufacture of hydrogen chloride. Explain.

In emulsion, dispersing medium is liquid whiledispersed phase is _____ .

In electroplating process the metal to be caoted is taekn as ________.

In Dobereiner's traids, the atomic weight of the middle element in the ………….of the atomic masses of 1st and 3rd elements.

In doberiener 's classification the atomic weight and the properties of the first element are almost equal to theaverage of those of the 2nd and 3rd elements of a triad

In Darjeeling, distilled water boils at a temperature

In cold countries, ethylene glycol is used car radiators for both winter as well as summer seasons. Explain.

In chlorine. argon, potassium and calcium, the number of electrons are 17, 18. 19, 20 and number of neutrons are 18, 22. 20, 20 respectively. Whlch pair of elements is isobars?

In aqueous solution, sodium sulphate (Na_(2)SO_(4)) dissociates into ions as follows . Na_(2)SO_(4)(aq) to 2Na^(+) (aq)+SO_(4)^(2-)(aq) Calculatethe number of ions produced when 23.75 g of sodium sulphateis dissolved in water .

Inan unsaturated solution more solute can be dissolved without increasingthe amount of the …………

In an orbit 32 electrons can be accomodated, then it will be ....... Orbit.(L, M, N)

In an atom, the mass number of an atom is equal to the number of ____.

In an atom, electrons revolve around the uncleus in fixed orbits.

In air, _____ is a solvent.

In Aerosol the dispersed phase is liquid and the dispersion medium is gas.

In a mixtureof chloroform and water , chloroform forms the .............. layers.

In a hypothetical reaction X to Y, the activation energies of the forward and backward reactions are 13 kj/mole and 7 kj/mole, respectively. Calculate heat of the reaction.

in a heterogeneous mixture , the constituents have no clear boundaries of separation.

In a dam , the surface water is at higher temperature than the water deep within the dam .

In a compound , the constituent elements are present in a fixed ratio by mass. This statement is called the law of ....................

In achemistry lab, Rina took some mercury and water in two test tubes separately. Then she drained off both the liquids and on observing the emty test tubes, found some difference. Can you guess what the difference is ? Explainwith appropriatereasons.

In a chemical compound , the constituent elements are present in …………. Proportions by weight .

In a certain reaction 2A + B hArr 4C, the concentration of A decreases from 5 xx 10^(-3) " mol"//L to 2 xx10^(-3) " mol"//L in 30 s. What is the rate with respect to C ?

In a canal ray experiment, different gases were found to produce canal rays with the same specific charge. Explain.

In ""_(47)^(108)Ag, state the number of protons, neutrons and electrons respectively.

In ""^(16)O_(8) the number 16 stands for

If Z = 3, what would be the valency of the element ? Also, name the element.

If ._x^yA^(+1) or ._(x-1)^(y-1)B^(+1) were to be used instead of alpha-particles in Rutherford's experiment, which would be better and why ?

If we keep a box of ice creasm in a freezer for too long, crystals of ice are formedinside the box. Give reasons.

If we consider each student in chain as a particle of matter, then in which group do the particles hold each other with the maximum force?

If we burn graphite

If Thomson's model is considered to be correct, what would be the obervation of Ruterford's alpha-ray scattering experiment?

If there are x atoms in 32 g sulphur, then how many atoms will be there in 32 g oxygen in terms of x?

If there are x atoms in 18 g carbon, then how many atoms will be there in 12 g magnesium ?

If the three elements X,Y and Z form a triad and atomic weights of X and Z are 9 and 40 respectively then the atomic weight of an element y is _________

If the temperature of an object is 268 K, it will be equivalent to :

If the number of electrons in an atom is 8 and the number of protons is also 8, then (i) What is the atomic number of the atom? and (ii) What is the charge on the atom?

If number of electrons in an atom is 8 and number of protons is also 8, then (i) what is the atomic number of the atom? and (ii) what is the charge on theatoms ?

If K and L shells of an atom are full, then what would be the total number of electrons in the atom?

If the energy difference between the orbits when an electron in H atom excited to higher energy orbit from its ground state is 12.1eV// atom , calcualte the frequency of radiation emitted (1 eV =1.602xx10^(-19J)) when electron comes back to second energy level.

If the atomic number of some elemetns in the modern periodic table are 8,7,11,12,13 and 9 what type of ions do they form? Arrange the ions in the increasing order of their size and justify

If the atomic number of some element in the modern periodioc table are8,7,11,12,13 and 9 what type of ions do they form ? Arrange the ions in the increasing order of their size and justify

If the activation energy of forward reaction is four times the amount of energy released (DeltaH= -10 kcal), what could be the activation energy of the backward reaction ?