2599 + Interview Questions in Chemistry in Class 9 Page 10 InterviewSolution

451.	Which of the folloiwng are matter? Chair, air, love, smell, hate, almonds, thought, cold, cold drink, smell of perfume.
Answer» SOLUTION :Chair, air, ALMONDS and cold DRINK are matters.

Discussion

452.	Which of the following is jelly ?
Answer» Ghee Sponge Milk Butter Answer :B

Discussion

453.	The symbol for cadmium is
Answer» Ca Cu CD Cm Solution :Cd

Discussion

454.	What is the need for chemical fertilizers in crop fields?
Answer» Solution :Chemical fertilizers PROVIDE the essential MICRO and MACRONUTRIENTS for crop growth that may not be SUFFICIENTLY AVAILABLE in the soil .

Discussion

455.	Which of the following substance is used as lining in Bessemer converter in case of acidic process?
Answer» QUICK LIME SILICA SLACKED lime CAUSTIC potash Solution :N/A

Discussion

456.	Which periods are called short periods and which periods are colled long periods? Why?
Answer»

Discussion

457.	What is the relation between surface area and rate of chemical reaction?
Answer» ANSWER :When SURFACE area increases the RATE or REACTION increases.

Discussion

458.	Which elements show similarity in chemical properties in groups and periods in the periodic table? (Noble gases, Representative elements transition elements, Lanthanoids)
Answer» ANSWER :TRANSITION ELEMENTS

Discussion

459.	What is the physical state of water at: a. 250^(@)C b. 100^(@)C
Answer» SOLUTION :a. At `250^(@)C` water in a gaseous STATE: b. At `100^(@)C` water is in liquid as well as gaseous state.

Discussion

460.	When soda waterbottle is kept open for sometime, it loses the tangy taste. Give reason.
Answer» Solution :At high pressure, more amount of `CO_2` is dissolved in water. When the bottle is opened, EXCESS amount of `CO_2`comes out as SOLUBILITY of GAS DECREASES in pressure, and HENCE, the soda water loses its tangy taste.

Discussion

461.	What is the valency of calcium in CaCO_(3)?
Answer» ANSWER :YES

Discussion

462.	Vikram is a student of class IX in a village school. He lives on the outkirts of th village in a farmhouse. There is an undergound oil pipeline going to an Oil Refinery in the area which passes near his farmhouse. One day Vikram found that a lot of workers had started digging the whole underground pipeline at some distance from his house. When he enquired about it, he was told that a leakage in oil pipeline (due to some crack, etc) is suspected in this area, so digging has to be done in a considerable area to find the place of leakage and set it right. Vikram asked the workers to stop digging all around. He said that he can pinpoint the place of leakage in the oil pipeline made of metal by using a certain procedure. Vikram then explained how the solution of a particular substance can be introduced in the pipeline carrying oil and the place of leakage of this substance can be detected by using a special instrument. The place of leakage of this substance will tell the place of crack in the pipeline from where the oil leaks. (a) What type of substance is used to dectect the leakage (or crack) in the underground oil pipeline ? (b) Which special instrument is used to detect the leakage of the above substance from the oil pipeline ? (c) Describe briefly, how the leakage in underground oil pipeline is detected by using the above particular substance and the special instrument (d) Which property/properties of the above mentioned particular substance introduced in the oil pipeline helps its detection above the ground ? (e) What is the advantage of using this substance in detecting the leakage in underground oil pipeline ? (f) What values are displayed by Vikram in this episode ?
Answer» Solution :(a) A radioacitve substance is used to DETECT LEAKAGE (or CRACK) in the underground oil pipeline (b) A Geiger counter is used to detect the radiations emitted by the leaking radioactive substance put in the oil pipeline (c) A small quantity of the solution of a radioactive substance is INTRODUCED oil pipeline in which the place of leakage is to be detected. This radiactive substance will leak out alongwith oil at the place where there is a crack in the METAL pipeline. A Geiger counter is moved over the surface of ground all along the burind oil pipeline. The are above the ground where a high intensity of radioactive radiations is detected by Geiger counter will pinpoint the place of leakage in pipeline. The underground pipeline can then be dug up at this place and crack in the pipeline can be repaired (d) The ratioactive substanceemites high energy radiations having high penetrating powder. Due to their high penetrating powder, radioactive radiations can pass through the layers of soil over the underground oil pipeline and hence can be detected by Geiger counter above the ground (e) The advantage of using a radioactive substance is that the place of leakage (or crack) in the underground oil pipeline can be pinpointed without digging up whole pipeline. This saves a lot of labour, time and money (f) The values displayed by Vikram in this episode are (i) Knowledge of the properties of radioactive substance (ii) Application of knowledge in solving everyday problem, and (iii) Helping nature.

Discussion

463.	Which of the followingis an element ?
Answer» MARBLE GRAPHITE WASHING soda baking soda Answer :B

Discussion

464.	What is the percentage composition of the elements in ammonia , NH_(3) ? (N = 14 , H = 1 )
Answer» SOLUTION :`N = 82. 35` % , H = 17.65 %

Discussion

465.	Which among the following has water of crystallisation ?
Answer» washig SODA baking soda common salt calcium hydroxide Solution :WASHING soda has WATER of CRYSTALLISATION.

Discussion

466.	When ammonia reacts with excess chlorine it forms
Answer» `NH_4CI+N_2` `N_2+HCI` `NOCI+HCI` `NCI_3+HCI` SOLUTION :`UNDERSET("EXCESS")(NH_3+3Cl_2)to NCI_3+2HCI`

Discussion

467.	Two elements X and Y have the same atomic mass but this atomic number are 20 and 21 respectively X and Y are
Answer» Isobar ISOTOPES ISOMERE ISOTONES ANSWER :B

Discussion

468.	What is the nature of magnesium oxide ?
Answer» SOLUTION :BASIC .

Discussion

469.	What type of clothes should we wear in summer?
Answer» Solution :We should wear cotton clothes in hot summer days to keep us cool and COMFORTABLE. This is due to the following reason : During hot summer days, we perspire more (give out more sweat through the pores of the skin). Sweat (pasina) is mainly water. The cotton clothes are good ABSORBER of sweat. So, cotton clothes absorb the sweat produced on our skin quickly and EXPOSE it to the atmosphere for EVAPORATION. The evaporation of sweat from cotton clothes takes the latent heat of vaporisation from our skin. In this way, our skin LOSES heat and makes us feel cool and comfortable.

Discussion

470.	When barium chloride solution is mixed with sodium sulphate solution …...
Answer» a WHITE PRECIPITATE is FORMED after some time. a YELLOW precipitate is formed INSTANTLY. a white precipitate is formed instantly. a yellow precipitate is formed after some time. Solution :a white precipitate is formed instantly.

Discussion

471.	The valency of element X is 1, so the molecular formula of the oxide of this element is ....... .
Answer» SOLUTION :`X_(2)O`

Discussion

472.	Which phenomeon occurs during the following changes? 1. formation of clouds, 2 Drying of wet clothes, 3. Wax melts in the sun, 4. The size of naphthalene balls decreases.
Answer» Solution :The phenomenon OCCURING during the CHANGES are as follows: 1. Condesation, 2. Evaporation, 3. FUSION (or liquefaction/melting) and 4. Sublimation.

Discussion

473.	Which are the electrons shows the chemical properties of elements?
Answer» ANSWER :OUTERMOST ELECTRONS.

Discussion

474.	What is the maximum number of electrons that can be accommodated in L shell? (L shell or 2nd orbit)
Answer» Solution :L shell can accommodate MAXIMUM 8 ELECTRONS. `[ 2N^(2) = 2 xx (2)^(2) = 2 xx 4 = 8 ] `

Discussion

475.	Which of the following statements are true for pure substances ? (i) Pure substances contain only one kind of particles (ii) Pure substances may be compounds or mixtures (iii) Pure substances have the same composition throughout (iv) Pure substances can be exemplified by all elements other than nickel.
Answer» (i) and (II) (i) and (III) (iii) and (iv) (ii) and (iii). SOLUTION :Both these statements are correct.

Discussion

476.	The soil pH of a crop land is 5. What kind of fertilizers should be used in that land?
Answer» Solution :Organic FERTILIZER LIKE compost can be USED to MAINTAIN pH of soil at 6.5, which is ideal for soil and to MODERATE the acidity.

Discussion

477.	Which of the following is false for molecular mass of hydrogen ?
Answer» 2 g `6.022 xx 10^(23)` hydrogen ATOMS `6.022 xx 10^(23)` hydrogen molecules 1 mole hydrogen Solution :`6.022 xx 10^(23)` hydrogen atoms

Discussion

478.	You are asked by your teacher to buy 10 mol of distilled water from a shop where small bottles each containing 20 g of such water are available . How many bottles will you buy ?
Answer» Solution :Molecular mass of water `(H_(2)O)= 18 `. `THEREFORE` 10 MOL of distilled water = `18 xx 10= 180` g . Because 20 g distilled water is contained in 1 bottle , 180 g of distilled water is contained in `(180)/(20)` BOTTLES = 9 bottles . `therefore` number of bottles to be bought = 9 .

Discussion

479.	Which subatomic partlcle is not present in hydrogen atom ?
Answer» PROTON Ncutron Proton and NEUTRON ELECTRON

Discussion

480.	The space between the particles of a solid is called intermolecular space.
Answer» ANSWER :T

Discussion

481.	Two containers A and B are filled with the same : amount of chlorine gas. Limited amount of methane is passed into container 'A' and excess of methane · into container 'B'. Identify the products formed in A and B. Give a reason in support of your answer.
Answer» Solution :(i) effect of amount of methane on product formation (ii) the initial product formed in container A (III) comparison of AMOUNTS of methane and prod uct present is container A with TIME (iv) comparison of reactivity of methane and product With chlorine (V) final products formed in container A (vi) product formed in container B based on avail- ability of reactant

Discussion

482.	Which of the following arechemical changes ? (a)growth of a Plant (b)Rusting of Iron ( c)Mixing ofIronFilingand sand (d)Cooking of Food ( e) Digestionof food ( f)Freezing of water ( g)Burning of Candle.
Answer» SOLUTION :CHEMICAL Changes :-Growth of Plants ,RUSTING of Iron ,COOKING of Food , Digestion of Food, BURNING of Candle

Discussion

483.	Which is the purest form of iron ? How is it useful ?
Answer» SOLUTION :N/A

Discussion

484.	Which one of the followingmixtures is a solution ?
Answer» soil sea water AIR SODA water Answer :B

Discussion

485.	Writesomeexample of the Elements?
Answer» SOLUTION :SODIUM, SILVER, TIN , SILICON

Discussion

486.	What was the basis for the propenol of Dalton's atomic theory ?
Answer» Solution :Laws sof chemical COMBINATION, such as, the LAW of conservation of mass, the law of definite proportions and the law of MULTIPLE proportions, were the basis for the PROPOSAL of Dalton's atomic theory.

Discussion

487.	Which of the following is a tetraatomic molecule ?
Answer» `O_(2)` `O_(3)` `NO_(2)` `SO_(3)` ANSWER :D

Discussion

488.	What is the latent heat of fusion of ice?
Answer» `33.4xx10^(5)JK^(-1)` `22.5xx10^(5)JKG^(-1)` `33.4xx10^(4)Jk^(-1)` `2.25xx10^(4)Jkg^(-1)` ANSWER :C

Discussion

489.	Which of the following elements has equal nic mass and molecular mass ?
Answer» Nitrogen NEON Oxygen Chlorine Solution :Neon

Discussion

490.	The valency of hydrogen is 1, magnesium, 2 aluminium 3 and carbon 4 . Can you see any connection between the valency of an element and the number of electrons it has in its outermost electron shell ?What would you predict the valencies of helium (He), phosphorus(P), sulphur (S) and neon (Ne) to be ?
Answer» SOLUTION :The valency of an element DEPENDS upon the number of electrons in the outermost shell (valence shell) of an atom of the element. The valency of an element is either equal to the number of valence electrons in an atom of the element or to the number of electrons requried to complete an octet of 8 electrons in its valence shell. Valency of a metal=number of valence electrons. Valency of a NONMETAL =8-number of valence electrons. Helium (He) : An atom of helium CONTAINS 2 electrons in its K shell (n=1) . This shell is also the outermost shell of helium which is completelyfilled with 2 electrons. Hence, valency of helium =0 . Phosphorus(P): The electronic configuration of the P atom is 2,8,5. Thus , it has 5 valence electrons and it is a nonmetal . Hence , valency of P =8-5=3. Sulphur (S) : The electronic configuration of an atom of S is 2,8,6. Sulphur is a nonmetal. Hence , valency of S=8-6=2 NEON (Ne): The electronic configuration of neon is 2,8. The outermost shell of neon is thus completely filled. Hence, valency of neon =0.

Discussion

491.	Which of the following is a ( are ) metalloid(s) ?
Answer» COPPER ARSENIC IRON Boron Answer :B::D

Discussion

492.	You are provided with a mixture containing sand, iron filings, ammonium chloride and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture?
Answer» Solution :Place the mixture on a paper or PETRIDISH. Move a bar magnet a number of times over the mixture. Iron filings get attached to the magnet and can be separated later on by scrapping. Transfer the remaining mixture to a china DISH and subject it to the sublimation process. Ammonium chloride sublimes leaving behind sodium chloride and sand. Transfer the mixture to a glass beaker. ADD a small amount of water and STIR with a glass rod for some time. Sodium chloride completely dissolves in water leaving behind sand as such. The latter can be removed by FILTRATION. The filtrate on concentration and cooling gives crystals of sodium chloride.

Discussion

493.	Which of the following energy is absorbed during the change of state of a substance ?
Answer» SPECIFIC HEAT LATENT heat heat CAPACITY heat of solution Answer :B

Discussion

494.	What is the physical state of water at a. 25^(@)C b. 0^(@)C c. 100^(@)C?
Answer» SOLUTION :a. Liquid STATE. B. Liquid as well as SOLID state. C. Liquid as well as gaseous state.

Discussion

495.	The symbol proposed by Dalton for gold is ......... .
Answer» SOLUTION :

Discussion

496.	What do you observe immediately after adding the ink drop?
Answer» SOLUTION :The COLOUR of INK STARTS SPREADING.

Discussion

497.	Water at room temperature is a liquid.
Answer» Solution :The particles of water have some FORCE of attraction AMONG them. The room temperature cannot provide SUFFICIENT heat to the particles to OVERCOME the force of attraction. Therefore, water REMAIN as a liquid at room temperature.

Discussion

498.	Write your observations when dilute sulphuric acid is added to the following: A metal sulphide (sodium sulphide).
Answer» SOLUTION :A GAS with offensive smell is EVOLVED which turns lead ACETATE PAPER black.

Discussion

499.	Which of the following are homogeneous in nature ? (i) Soda water (ii) Coal (iii) Air (iv) Wood
Answer» (i) and (II) (i) and (III) (ii) and (iii) (iii) and (IV) ANSWER :A::D

Discussion

500.	The substance X normally exists in a physical state whichcan flow easily but does not fill its vessel completely. It also turns anhydrous copper sulphate blue. When substance X is cooled excessively, it changes into a substance Y which has a fixed shape as well as a fixed volume. If, however, the substance X is heated strongly, it changes into a substance Z which has neither a fixed shape nor a fixed volume. (a) Name the substances X. (b) What is the process of conversion of X into Y known as ? (c ) At which temperature X gets converted into Y ? (d) What is the process of conversion of X into Z known as ? (e ) At which temperture X gets converted into Z ?
Answer» Solution :(a) The substance X is water since it turns anhydrous copper sulphate blue. (b) The substance Y is ice since water changes to ice upon EXCESSIVE cooling. The process of CONVERSION of X into Y is KNOWN as freezing. (c ) The TEMPERATURE called freezing point of water is `0^(@)C` or 273 K. (d) Water upon HEATING gets converted into steam (Z) and the process is known as boiling. (e ) X gets converted into Z at its boiling point temperature. It is `100^(@)C` or 373 K.

Discussion

Explore topic-wise InterviewSolutions in .

Which of the folloiwng are matter? Chair, air, love, smell, hate, almonds, thought, cold, cold drink, smell of perfume.

Which of the following is jelly ?

The symbol for cadmium is

What is the need for chemical fertilizers in crop fields?

Which of the following substance is used as lining in Bessemer converter in case of acidic process?

Which periods are called short periods and which periods are colled long periods? Why?

What is the relation between surface area and rate of chemical reaction?

Which elements show similarity in chemical properties in groups and periods in the periodic table? (Noble gases, Representative elements transition elements, Lanthanoids)

What is the physical state of water at: a. 250^(@)C b. 100^(@)C

When soda waterbottle is kept open for sometime, it loses the tangy taste. Give reason.

What is the valency of calcium in CaCO_(3)?

Which of the followingis an element ?

What is the percentage composition of the elements in ammonia , NH_(3) ? (N = 14 , H = 1 )

Which among the following has water of crystallisation ?

When ammonia reacts with excess chlorine it forms

Two elements X and Y have the same atomic mass but this atomic number are 20 and 21 respectively X and Y are

What is the nature of magnesium oxide ?

What type of clothes should we wear in summer?

When barium chloride solution is mixed with sodium sulphate solution …...

The valency of element X is 1, so the molecular formula of the oxide of this element is ....... .

Which phenomeon occurs during the following changes? 1. formation of clouds, 2 Drying of wet clothes, 3. Wax melts in the sun, 4. The size of naphthalene balls decreases.

Which are the electrons shows the chemical properties of elements?

What is the maximum number of electrons that can be accommodated in L shell? (L shell or 2nd orbit)

The soil pH of a crop land is 5. What kind of fertilizers should be used in that land?

Which of the following is false for molecular mass of hydrogen ?

You are asked by your teacher to buy 10 mol of distilled water from a shop where small bottles each containing 20 g of such water are available . How many bottles will you buy ?

Which subatomic partlcle is not present in hydrogen atom ?

The space between the particles of a solid is called intermolecular space.

Two containers A and B are filled with the same : amount of chlorine gas. Limited amount of methane is passed into container 'A' and excess of methane · into container 'B'. Identify the products formed in A and B. Give a reason in support of your answer.

Which of the following arechemical changes ? (a)growth of a Plant (b)Rusting of Iron ( c)Mixing ofIronFilingand sand (d)Cooking of Food ( e) Digestionof food ( f)Freezing of water ( g)Burning of Candle.

Which is the purest form of iron ? How is it useful ?

Which one of the followingmixtures is a solution ?

Writesomeexample of the Elements?

What was the basis for the propenol of Dalton's atomic theory ?

Which of the following is a tetraatomic molecule ?

What is the latent heat of fusion of ice?

Which of the following elements has equal nic mass and molecular mass ?

Which of the following is a ( are ) metalloid(s) ?

You are provided with a mixture containing sand, iron filings, ammonium chloride and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture?

Which of the following energy is absorbed during the change of state of a substance ?

What is the physical state of water at a. 25^(@)C b. 0^(@)C c. 100^(@)C?

The symbol proposed by Dalton for gold is ......... .

What do you observe immediately after adding the ink drop?

Water at room temperature is a liquid.

Write your observations when dilute sulphuric acid is added to the following: A metal sulphide (sodium sulphide).

Which of the following are homogeneous in nature ? (i) Soda water (ii) Coal (iii) Air (iv) Wood