908 + Interview Questions in Chemistry in Class 7

1.	Mention suitable terms for the following statements. (a) Decrease in density of water on decreasing temperature from 4^(@)C to 0^(@)C which is opposite to the normal trend. (b) The undergroundlayer of water bearing permeable rock present below the water table (c ) The natural process of adding water to atmospheric air and its subsequent condensation to rain water. (d) Type of chemical reaction carried out when electricity is passed through water.
Answer» Solution :(a) ANOMALOUS expansion of water (B) AQUIFER (C ) Water cycle (d) Decomposition reaction

Discussion

2.	Mention some specific properties of metals.
Answer» SOLUTION :Some specific properties of metals are LUSTRE, tensile STRENGTH, CONDUCTIVITY, malleability etc.

Discussion

3.	Mention methods for preventing acid rain.
Answer» Solution :Methods of prevention of acid rain. (i) Minimizing the use of fossil fuels. Fossil fuels such as PETROL, diesel are replaced by CNG to a GREAT extent in some metropolitan CITIES. (ii) Using non convertional sources of energy. (iii) Safe disposal of industrial WASTES.

Discussion

4.	Mention few properties of mercury.
Answer» Solution :Properties of mercury (i) It is silvery white LIQUID metal at normal temperature. (ii) Ist melting point is ` - 39^(@) C` andboiling point is ` 357^(@) C` . (iii) It is very GOOD conductor of ELECTRICITY and heat. (iv) It can DISSOLVE almost all metals in it.

Discussion

5.	Mention different types of combination reactions with example.
Answer» SOLUTION :`{:("TYPE","Example"),("ELEMENT - element (synthesis)",H_(2)+Cl_(2) to2HCl),("Element - compound",2SO_(2)+O_(2)to2SO_(3)),("Compound - compound",CaO+H_(2)OtoCa(OH)_(2)):}`

Discussion

6.	Mention any four physical properties of CO_(2).
Answer» Solution :Physical properties of `CO_(2)` (1) It is colourless and ODOURLESS gas. (2) It is highly soluble in water. (3) `CO_(2)` is acidic in nature (4) It is heavier than air.

Discussion

7.	Mention any four important uses of hydrogen.
Answer» Solution :Important uses of hydrogen is as follows (1) In the SYNTHESIS of industrial chemicals such as ammonia, `CHI, CH_(3)OH`ETC. (2) It is used in the manufacture of fuel GASES such as water gas, coal gas, semi-water gas etc. (3) It is used for welding of metals. (4) It is used as a good reducing agent in the extraction of some metals from their oxides.

Discussion

8.	Melting of wax is a ________.
Answer» CHEMICAL CHANGE decomposition reaction both PHYSICAL and chemical change physical change Solution :MELTING of WAX is a physical change

Discussion

9.	Match the following{:(,"Column - A",,,"Column - B"),((A),"Rain water","()",(a),"Free of suspended impurities."),((B),"Rivers and lakes","()",(b),"Purest form of natural water."),((C),"Underground water","()",(c),"Water obtained after reverse osmosis."),((D),"Demineralized water","()",(d),"Water coming out of an ion exchange apparatus."),(,,"()",(e),"Fresh water for consumption for various activities."):}
Answer» A `rarr` c, B `rarr` b, C `rarr` a, D `rarr` d, e A `rarr` b, B `rarr` e, C `rarr` a, D `rarr` d A `rarr` b, B `rarr` a, C `rarr` d, D `rarr` e A `rarr` b, B `rarr` a, e, C `rarr` c D `rarr` d Solution :A `rarr` b:RAIN water is the purest FORM of natural water. B `rarr` e:River and lake water is considered as fresh water and is available for CONSUMPTION for various activities C `rarr` a: Underground water during seepage gets filtered through various layers of SOIL and hence does not contain suspended impurities. D `rarr` d:The water coming out of an ion exchange APPARATUS contains only pure water and is called dematerialized water.

Discussion

10.	Match the following {:(,"Column A",,,"Column B"),((A),CuSO_(4),(),(a),"Hygroscopic"),((B),Na_(2)CO_(3)*10H_(2)O,(),(b),"Deliquescent"),((C),"Concentrated" H_(2)SO_(4),(),(c),"Efflorescent"),((D),ZnC1_(2),(),(d),"Anhydrous salt"):}
Answer» `A rarr B, B rarr c, C rarr d, D rarr a` `A rarr d, B rarr c, C rarr a, D rarr b` `A rarr c, B rarr d, C rarr b, D rarr a` `A rarr c, B rarr d, C rarr a, D rarr b` Solution :A `rarr` d `CuSO_(4`) is an example of anhydrous salt. B `rarr` c `Na_(2)CO_(3)*10H_(2)O` is an example of efflorescent SUBSTANCE. C `rarr` a Conc. `H_(2)SO_(4)` is an example of hygroscopic substance. D `rarr` b `ZnCI_(2)` is an example of deliquescent substance.

Discussion

11.	Match the Following{:(,"Column - A",,,"Column - B"),((A),"Distilled water","()",(a),"Drinking purpose"),((B),"Potable water","()",(b),"Laboratory work"),((C),"Spring water","()",(c),"Dissolved salts and rare minerals"),((D),"Acidulated water","()",(d),"Medicinal purposes"),(,,"()",(e),"Electrolysis"):}
Answer» A `rarr` b, B `rarr` a, C `rarr` d, c, D `rarr`e A `rarr` c, B `rarr` b, C `rarr` c, e, D `rarr` d A `rarr` b, B `rarr` c, C `rarr` d, D `rarr` e A `rarr` a, B `rarr` c, e, C `rarr` d, e,D `rarr` d Solution :A `rarr` b: Distilled water is used in laboratory for chemical reactions taking place in water. B `rarr` a: POTABLE water is used for drinking purpose. C `rarr` d, c: Spring water is DEVOID of suspended impurities but contains dissolved salts and minerals. Due to the presence of rare minerals it is used for medicinal purposes. D `rarr` e: Pure water is a bad conductor of ELECTRICITY,little AMOUNT of sulphuric acid is added to make acidulated water.

Discussion

12.	Match the following. {:(,"Column A",,,"Column B"),((A),"CaO",(),(a),"Deliquescent"),((B),MgC1_(2)6H_(2)O,(),(b),"Hydrated salt, but not deliquescent"),((C),FeSO_(4)7H_(2)O,(),(c),"Anhydrous and deliquescent salt"),((D),MgSO_(4),(),(d),"Hygroscopic"):}
Answer» `A rarr d, B rarr a, C rarr b, D rarr c` `A rarr a, B rarr d, C rarr b, D rarr c` `A rarr b, B rarr c, C rarr d, D rarr a` `A rarr d, B rarr c, C rarr b, D rarr a` Solution :A `rarr` d CaO is an example of hygroscopic substance. B `rarr` a `MgC1_(2)` is an example of DELIQUESCENT substance. C `rarr` b `FeSO_(4)*7H_(2)O` is an example of hydrated salt. D `rarr` c `MgSO_(4)` is an example of anhydrous salt.

Discussion

13.	Match the element in column A with the electronic configuration given in column B.{:(,"Column A",,,"Column B"),((A),"Chlorine",(),(a)," "2_(,)2),((B),"Scandium",(),(b)," "2_(,)8_(,)7_(,)),((C),"Manganese",(),(c)," "2_(,)8_(,)9_(,)2),((D),"Beryllim",(),(d)," "2_(,)8_(,)13_(,)2):}
Answer» `AtoC,""Btod,"" Ctoa, "" Dtob` `Atod,"" Btoa, "" Ctob, "" Dtoc` `Atob,"" Btoa, "" CTOD, "" Dtoa` `Atod,"" Btoa, "" Ctoc, "" Dtob` Solution :`Atob` Atomic number of chlorineis 17 , electronic configuration is 2 , 8 , 7 `Btoc` Atomic number of scandium is 21, electronic configuration is 2 , 8 , 9 , 2 ` Ctod` Atomic number of manganese is 25 , electronic configuration is 2 , 8 , 13 , 2 `Dto a` Atomic number of BERYLLIUM is 4 , electronic configuration is 2 , 2

Discussion

14.	Match the element in column A with thevalency exhibited by the element given in column B{:(,"Column A",,,"Column B"),((A),"Neon",(),(a),""4),((B),"Oxygen",(),(b),""3),((C),"Potassium",(),(c),""2),((D),"Boron",(),(d),""1),((E),"Silicon",(),(d),""0):}
Answer» `ATOB,"" Btoc," " Ctod, " " Dtoe," " Etoa` `Atob,"" Btoc," " Ctoa, " " Dtoe," " Etod` `Atoe,"" Btod," " Ctoa, " " Dtob," " Etoc` `Atoe,"" Btoc," " Ctod, " " Dtob," " Etoa` Solution :`Atoe` Atomic NUMBEROF neon is 10 and electronic configuration 2 , 8 valency is zero. `Btoc` Atomic numberof oxygen is 8 and electronic configuration 2 , 6 valency= 8 - 6 = 2 `Cto d` Atomic number of potassium is 19AND electronic configuration is 2 , 8 , 8 ,valency = 1 `Etoa` Atomic number of SILICON is 14 and electronic cofiguration is 2 , 8 , 4 valency = 4

Discussion

15.	Master Vishnu and his sister Jishnu went to their uncle's village to spend their summer vacation. One day, Jishnu was pestering her uncle for a soft drink. Vishnu's uncle took both of them to a shop where soft drink bottles were kept in an insulated box containing ice. Vishnu's uncle who is a physical science teacher, with an intention of testing Vishnu, posed a question to him regarding the concept involved in cooling of soft drinks by keeping them in ice. Vishnu who is a student of Time, IITF impressed his uncle by explaining the above phenomenon with respect to the concept of latent heat of fusion of ice. Can you also explain the concept like Vishnu?
Answer» Solution :The amount of heat energy required to CONVERT 1 G of ice to 1 g of WATER at `0^(@)C` is called latent heat of fusion. Latent heat of fusion of ice is 80 cal/g that is every 1 g of ice requires 80 calories of heat in order to melt. This energy is TAKEN away from the soft drinks and hence soft drinks are cooled when they are placed in ice.

Discussion

16.	Mass of total positive charge present in anatom is7348 times to that of the mass of a negativity charged particle . Findthe atomic number of an element . Find out its valency.
Answer» Solution :Massof a proton is 1837 times that of electron `{:("MASS of one proton",=,1837),(""?,----,7348),((7348)/(1837)=4,,):}` Hence the ATOMIC NUMBER is 4.Electronic arrangement is 2 , 2 . Itcan lose 2 electrons to ATTAIN duplet configuration and hence it forms`Be^(+2)` ion. Hence its valency is' +2'.

Discussion

17.	Mass of total positive charge present in an atom is 55110times to thatofmass of electron . Write the electronic configuration of the element.
Answer» 2,8 ,9 ,2 2 ,8 , 18 , 1 2, 8 , 18, 2 2 ,8 , 82 Solution :We know that mass of a proton is1837 times that of an ELECTRON. `:.`ATOMIC number of element`=(55110)/(1837)=30` `:.`Electronic configuration of the elementis2 , 8 , 18 , 2

Discussion

18.	Magnesium attains an octet configuration by ________ electrons.
Answer» Solution :losing two Electronic ARRANGEMENT of Mg is 2 , 8 , 2 . By losing two electrons , it ATTAINS octet configuration.

Discussion

19.	List out the important uses of CO_(2).
Answer» Solution :USES of carbon dioxde (i) It is used in soft drinks. (II) It is used in refrigeration system. (iii) It is used as a fire extinguisher. (IV) It is used in the manufactrure of diffferent chemicals like `H_(2)SO_(4),HNO_(3)` etc

Discussion

20.	List important uses of water.
Answer» Solution :Important USES of water: (i) Essential constituents for the reaction of PHOTOSYNTHESIS which is the process providing supporter of life as well as making FOOD for plants and animals. (ii) Mediumfor all BIOCHEMICAL processes taking place in plants and animals. (iii) Transport of nutrients and MINERALS to the living cells in living beings. Regulation of body temperature.

Discussion

21.	Limestone is used in the manufacture of
Answer» quick LIME glass cement all of these SOLUTION :Lime STONE is one of the RAW materials used for the manufacture of quicklime, glass andcement.

Discussion

22.	Lime water is a _________
Answer» mixture element compound All the above Solution :Lime water is a SATURATED solution of CALCIUM hydroxide HENCE it is a mixture

Discussion

23.	Legumious plants do not require the addition of nitrogenous fertilizers because
Answer» they can FIX up atmospheric nitrogen. of the presence of rhizobium bacteria in their ROOT nodules. they posses nitrogen in roots hence do not REQUIRE external intake. Both (1) and (2) Solution :Leguminouw PLANTS consist of nodules in their roots with rhizobium bacteria. This bacteria converts atmospheric nitrogen into its corresponding metal nitrates. These nitrates can be readily assimilated by plants. Hence, they do not require additional ntrogenous fertilizers.

Discussion

24.	Lead sulphid is a normal salt.
Answer» Solution :Normal salt is FORMED by COMPLETE REPLACEMENT of the hydrogen IONS of an acid with metal ions. Ex: PbS

Discussion

25.	Lead is used for making fusible alloy constituted of lead and tin in ________ ratio by mass.
Answer» `1 : 2` ` 2 : 1` ` 1: 3` ` 1 : 1` SOLUTION :Lead is USED for making fusible ALLOY constituted lead andtin in ` 1: 1` ratio by MASS.

Discussion

26.	Latent heat of vapourisation of water is ______
Answer» 270 cal/g 540 cal/g 80 cal/g 180 cal/g Solution :Latent HEAT of VAPOURIZATION of water is 540 cal/g.

Discussion

27.	Jini took a container completely filled with some ice cubes floating on it. He observed the container expecting that water to overflow after the ice melted. Can you predict what he would finally see?
Answer» Solution :The water WOULD not OVERFLOW after the melting of the ICE cubes because the volume of water obtained from the ice cubes is equal to the volume of water DISPLACED by the ice cubes. The container would be FILLED up to the brim.

Discussion

28.	Jack was getting late for the school, so, his mother advised him to pour hot milk from a glass into a saucer and then drink. Why did she say so? Give reason.
Answer» Solution :RATE of evaporation depends on surface AREA of liquids. The more is the surface area of the liquid, the more is the rate of evaporation of the liquid. This is due to increased number of SUFACE molecules. When these surface molecules are exposed to atmosphere, they GAIN energy and escape into atmosphese. And hence hot milk in the saucer gets cooled.

Discussion

29.	Iron powder and powder of rust are taken in two containers X and Y respectively. Dilute sulphuric acid is added to both the containers. Then
Answer» EFFERVESCENCE is observed in two containers. effervescence is observed in case of X but not Y. effervescence is observed in case of Y but not X. no effervescence is observed in both cases. Solution :Iron is an element and rust is a compound of iron in which iron does not retain its properties and hence rust does not LIBERATE hydrogen GAS with dilute sulphuric acid and no effervescence is observed in container Y.

Discussion

30.	Iron powder and powder of rust are taken in two containers X and Y respectively. Dilute sulphuric acid is added two containers
Answer» EFFERVESCENCE is observed in both the containers. Effervescence is observed in X but not in Y. Effervescence is observed in Y but not in X. No effervescence is observed in any of the containers. Solution :Iron is an ELEMENT and rust is a COMPOUND of iron in which iron does not retain its properties and hence rust does not LIBERATE hydrogen gas with dilute sulphuric acid and no effervescence is observed in container Y.

Discussion

31.	Iodized salt does not contain the following compound
Answer» sodium iodide POTASSIUM iodide common salt LITHIUM iodide Solution :The common salt CONTAINING sodium iodide, andpotassium iodide is called iodized salt. Lithium iodide is not PRESENT in the iodized salt.

Discussion

32.	Iodine is a lustrous metal.
Answer» SOLUTION :FALSE IODINE is a LUSTROUS non-metal.

Discussion

33.	Iodine in a mixture of potassium iodide and alcohol is called _________
Answer» SOLUTION :TINCTURE of iodine Iodine in a mixture of POTASSIUM iodide and alcohol is called tincture of iodine.

Discussion

34.	Intermolecular space is maximum in gases.
Answer» Solution :TRUE gases have maximum INTER MOLECULAR SPACES.

Discussion

35.	Incomplete combustion of fuels doesn't contribute to
Answer» photochemical smog acid rain GLOBAL warming Both (1) and (2) Solution :INCOMPLETE combustion of FUELS releases CO, NO, ETC, that LEADS to photochemical smogs and acid rain but not global warming.

Discussion

36.	In which way is greenhouse effect useful to us ?
Answer» SOLUTION :Greengouse EFFECT HELPSTO maintaiin TEMPERATURE of the EARTH.

Discussion

37.	In…………, the temperature decreases with the increase in altitude.
Answer» IONOSPHERE troposphere ozonosphere stratosphere Solution :In TROPOSHERE the temperrature DECREASES with the icreses in ALTITUDE.

Discussion

38.	In the table given below , some compounds are listed . In listed . In each case , identify the positive and negative radicals present in the compound.{:(,,"Positive radical","Negative radical"),("No".,"Compound",,),(("i"),CaSiO_(3),,),(("ii"),H_(2)SO_(3),,):}
Answer» Solution :`underset({:(Ca^(2+),SiO_(3)^(-2),H^(+),SO_(3)^(-2)),("POSITIVE","NEGATIVE","Positive","Negative"),("RADICAL","radical","radical","radical"):})(CaSiO_(3)""H_(2)SO_(3))`

Discussion

39.	In thetable given below , some commonly used positiveand negative radicals are listed . Use the crisscross method to obtain the formulae of the compound that is formed using the given radicals . Namethe compound thus obtained.{:("No.","Positive radicals","Nagative radicals","Formula","Name of the compound"),(1.,Al^(+3),PO_(4)^(-3),,),(2.,Ca^(+2),NO_(3)^(-1),,),(3.,NH_(4)^(+1),SO_(4)^(-2),,),(4.,Al^(+3),Ca^(-4),,):}
Answer» Solution :(1)`AlPO_(4) to `Aluminium PHOSPHATE (2)`Ca(NO_(3))_(2)to`Calcium nitrate (3)`(NH_(4))_(2)SO_(4)to`Ammonium phosphate (4)`Al_(4)C_(3)to`Aluminium CARBIDE

Discussion

40.	In the laboratory preparation of oxygen from gydrogen peroxide, ………… is used as a catalyst.
Answer» Solution :`MnO_(2)` In the LABORATORY PREPARATION of oxygen from hydrogen PEROXIDE, `MnO(2)` is used as a catalyst.

Discussion

41.	In theformation of sodium chloride , each chlorine gains_________ electron.
Answer» SOLUTION :ONE chlorine gains an ELECTRON while sodium loses an electron to FORM NaCl.

Discussion

42.	In sedimentation process, alum ______ the process of precipitation of suspended impurities.
Answer» Solution :In SEDIMENTATION process, ALUM hastens the process of PRECIPITATION of SUSPENDED IMPURITIES.

Discussion

43.	In phosphide ion , the total number of electrons is equal to 12.
Answer» <P> SOLUTION :FALSE `p^(3)=15+3=18`ELECTRONS.

Discussion

44.	In permutit process, what is the role of the addition of the concentrated solution of the solidcompound obtained due to the reaction between NaOH with HCl? Explain.
Answer» SOLUTION :In permutit process, we use sodium permutit that is., `Na_(2)Al_(2)Si_(2)O_(8).x H_(2)O`. When hard water is treated with sodium premutit, Ca and Mg ions are EXCHANGE with the Na ions present in the permutit. After long use, most of the sodium ions present in permutit are REPLACED with calcium and magnesium ions and HENCE it becomes ineffective. Sodium hydroxide reacts with Hcl to from sodium chloride Concentrated sodium chloride solution is added to regenerate the permutit.

Discussion

45.	In …………… layer of atmosphere TV waves to not get reflected. Hence artificial satellites are used for television.
Answer» Solution :In tge IONOSPHERE a layer of atmosphere, TV waves do not get REFLECTED, Hence artificial SATELLITES are USED for transmission of TV waves.

Discussion

46.	In electrolysis of water ______ gas is liberated at cathode.
Answer» Solution :In electrolysis of WATER hydrogen gas is LIBERATED at CATHODE.

Discussion

47.	In Chemistry practical examination, three friends DEAN, BEAN, and SEAN were given test tubes. A, B, and C filled with solutions respectively. DEAN added blue litmus, BEAN added methyl orange and SEAN added the litmus solution to the given test tube respectively. DEAN found blue litmus turning red, BEAN observed methyl orange turning yellow but SEAN found no action in solution provided to him in the test tube. Comment on the nature of the theree solutions given.
Answer» Solution :As A turns BLUE LITMUS to red, it is acidic in NATURE. As B turns methyl orange to yellow, it is basic in nature. As "C" is neutral TOWARDS both the litmus, it is neutral in nature i.e., a normal salt solution.

Discussion

48.	In 'Aqua Regia' quiz competition the quiz master asked one of the teams to name the two hardest substances one of which is naturally occurring and the other one is manmade. As none of the teams could give the correct answer. he gave a clue that both thesubstances are used for cutting glass anddrilling rocks and contain one common element. Then one of the teams gave the correctanswers. What could be theright answer ?
Answer» Solution :DIAMOND and silicon carbide are the two HARDEST substances KNOWN. Since diamond occures naturally one is diamond and the other is silicon carbide as it is OBTAINED by the reaction between carbon and silicon. The common element present in diamond andsilicon cardide is carbon.

Discussion

49.	In an atom , L and M shells have the same number of electrons . N shell has one electron less than K shell . Explain the formation of compound by this element and oxygen atom.
Answer» Solution :Theelectronic arrangement of the element COULD be 2 , 8 , 8 , 1 it corresponds to Z =19 and element is POTASSIUM . Oxygen requires 2 electronic arrangement of 2 , 6 . Potassium loses oneelectron to form K+ ion , oxygen requires 2 electronicto complete its octet . therefore it TAKES 2 electrons from two potassium atoms FORMS `K_(2)O`.

Discussion

50.	In a science exhibition, a student called Rishi performed the following experiment. She took two containers of the same dimensions and filled one of them with wax and the other one with ice. She placed both of them in a boiling water bath. What difference could she observe during the melting of these two substances? Also predict the reason for the observed difference.
Answer» Solution :Since the density of solid wax is GREATER than the molten wax, molten wax will OVERFLOW. Density of ice is less than that of water. As a result, water FORMED from ice occupy LESSER VOLUME instead of overflowing.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Mention some specific properties of metals.

Mention methods for preventing acid rain.

Mention few properties of mercury.

Mention different types of combination reactions with example.

Mention any four physical properties of CO_(2).

Mention any four important uses of hydrogen.

Melting of wax is a ________.

Match the following {:(,"Column A",,,"Column B"),((A),CuSO_(4),(),(a),"Hygroscopic"),((B),Na_(2)CO_(3)*10H_(2)O,(),(b),"Deliquescent"),((C),"Concentrated" H_(2)SO_(4),(),(c),"Efflorescent"),((D),ZnC1_(2),(),(d),"Anhydrous salt"):}

Match the following. {:(,"Column A",,,"Column B"),((A),"CaO",(),(a),"Deliquescent"),((B),MgC1_(2)*6H_(2)O,(),(b),"Hydrated salt, but not deliquescent"),((C),FeSO_(4)*7H_(2)O,(),(c),"Anhydrous and deliquescent salt"),((D),MgSO_(4),(),(d),"Hygroscopic"):}

Match the element in column A with the electronic configuration given in column B.{:(,"Column A",,,"Column B"),((A),"Chlorine",(),(a)," "2_(,)2),((B),"Scandium",(),(b)," "2_(,)8_(,)7_(,)),((C),"Manganese",(),(c)," "2_(,)8_(,)9_(,)2),((D),"Beryllim",(),(d)," "2_(,)8_(,)13_(,)2):}

Match the element in column A with thevalency exhibited by the element given in column B{:(,"Column A",,,"Column B"),((A),"Neon",(),(a),""4),((B),"Oxygen",(),(b),""3),((C),"Potassium",(),(c),""2),((D),"Boron",(),(d),""1),((E),"Silicon",(),(d),""0):}

Mass of total positive charge present in anatom is7348 times to that of the mass of a negativity charged particle . Findthe atomic number of an element . Find out its valency.

Mass of total positive charge present in an atom is 55110times to thatofmass of electron . Write the electronic configuration of the element.

Magnesium attains an octet configuration by ________ electrons.

List out the important uses of CO_(2).

List important uses of water.

Limestone is used in the manufacture of

Lime water is a _________

Legumious plants do not require the addition of nitrogenous fertilizers because

Lead sulphid is a normal salt.

Lead is used for making fusible alloy constituted of lead and tin in ________ ratio by mass.

Latent heat of vapourisation of water is ______

Jini took a container completely filled with some ice cubes floating on it. He observed the container expecting that water to overflow after the ice melted. Can you predict what he would finally see?

Jack was getting late for the school, so, his mother advised him to pour hot milk from a glass into a saucer and then drink. Why did she say so? Give reason.

Iron powder and powder of rust are taken in two containers X and Y respectively. Dilute sulphuric acid is added to both the containers. Then

Iron powder and powder of rust are taken in two containers X and Y respectively. Dilute sulphuric acid is added two containers

Iodized salt does not contain the following compound

Iodine is a lustrous metal.

Iodine in a mixture of potassium iodide and alcohol is called _________

Intermolecular space is maximum in gases.

Incomplete combustion of fuels doesn't contribute to

In which way is greenhouse effect useful to us ?

In…………, the temperature decreases with the increase in altitude.

In the table given below , some compounds are listed . In listed . In each case , identify the positive and negative radicals present in the compound.{:(,,"Positive radical","Negative radical"),("No".,"Compound",,),(("i"),CaSiO_(3),,),(("ii"),H_(2)SO_(3),,):}

In the laboratory preparation of oxygen from gydrogen peroxide, ………… is used as a catalyst.

In theformation of sodium chloride , each chlorine gains_________ electron.

In sedimentation process, alum ______ the process of precipitation of suspended impurities.

In phosphide ion , the total number of electrons is equal to 12.

In permutit process, what is the role of the addition of the concentrated solution of the solidcompound obtained due to the reaction between NaOH with HCl? Explain.

In …………… layer of atmosphere TV waves to not get reflected. Hence artificial satellites are used for television.

In electrolysis of water ______ gas is liberated at cathode.

In an atom , L and M shells have the same number of electrons . N shell has one electron less than K shell . Explain the formation of compound by this element and oxygen atom.

Match the following. {:(,"Column A",,,"Column B"),((A),"CaO",(),(a),"Deliquescent"),((B),MgC1_(2)6H_(2)O,(),(b),"Hydrated salt, but not deliquescent"),((C),FeSO_(4)7H_(2)O,(),(c),"Anhydrous and deliquescent salt"),((D),MgSO_(4),(),(d),"Hygroscopic"):}