8881 + Interview Questions in Chemistry in Class 10 Page 26 InterviewSolution

1251.	When reddish brown copper metal is heated it forms a black solid surface. Which of the following statement is incorrect ?
Answer» BLACK solid SUBSTANCE is CuO. It is redox reaction, It is precipitation reaction. COPPER UNDERGO oxidation. Solution :It is precipitation reaction.

Discussion

1252.	Write the formula used to determine the maximum numbers of electrons which a shell in an atom can accommodate.
Answer» SOLUTION :The formula USED to determine maximum NUMBER of electrons is 2ND where .n. is the shell number.

Discussion

1253.	What is the product [H^(+)] xx [OH^(-)] called ?
Answer» SOLUTION :IONIC PRODUCT of WATER.

Discussion

1254.	Two elements ‘A’ and 'B' belong to the 3rd period of Modern periodic table and are ingroup 2 and 13 respectively. Compare their following characteristics in tabular form: (a) Number of electrons in their atoms (b) Size of their atoms (c) Their tendencies to lose electrons (d) The formula of their oxides (e) Their metallic character The formula of their chlorides
Answer» SOLUTION :

Discussion

1255.	What is a balanced chemical equation? Why should the chemical equations be balanced?
Answer» Solution :A balanced chemical equation is one which contains an equal number of atoms of each element on both sides of the equation. For example, `2H_(2)+O_(2)rarr2H_(2)O` According to the law of CONSERVATION of mass, matter can neither be created nor DESTROYED in a chemical reaction. During a chemical reaction, the TOTAL mass of reactants and products remain the same. HENCE, in a chemical reaction, the number of atoms of the various elements on both sides should be equal. Therefore, a chemical equation is to be balanced in ACCORDANCE with the law of conservation of mass.

Discussion

1256.	When sodium chloride is dissolved in water the solution obtained is
Answer» Homogeneous. HETEROGENEOUS non - UNIFROM in COMPOSITION TURBID Answer :A

Discussion

1257.	Which of the following is acidic in nature ?
Answer» LIME juice HUMAN blood Lime water ANTACID Solution :Lime juice is acidicin nature because it CONTAINS citric acid. Human blood is slightly basic (i.e., having pH 7.8) Lime water and antacid are basic in nature as they contain hydroxide `(OH^(-))` ion.

Discussion

1258.	What is the common name of the elements of group 1?
Answer» SOLUTION :ALKALI METALS

Discussion

1259.	Which of the following statements about the given reaction are correct ? 3Fe(s)+4H_(2)O(l)toFe_(3)O_(4)(s)+4H_(2)(g)
Answer» IRON is oxidised water is REDUCED water acts as REDUCING AGENT water acts as oxidising agent ANSWER :A

Discussion

1260.	Which of the following statements is valid for a mixture ?
Answer» It is ALWAYS homogeneous . The COMPONENTS do not have their individual properties. The components retain their individual properties. none of the above Answer :D

Discussion

1261.	What are the methods preventing corrosion ?
Answer» Solution :Methods of preventing corrosion : Alloying : (i) The metals can be alloyed to prevent the process of corrosion . (ii) E.g: Stainless Steel SurfaceCoating : It involvesapplication of a protectivecoating over the metla. It is of the following types : (a) Galvanization : It is the process of coatingzinc on iron sheets by USING electric current . (b) Electroplating : It is a method of coatingone metal over anothermetal by passingelectric current . (c) Anodizing : (i) It is an ELECTROCHEMICAL process . (ii) It convertsthe metal surface into a DECORATIVE, durableand corrosion resistant . (iii) Aluminium is widely used for anodizing process . (d) Cathodic Protection : (i) It is the methodof controllingcorrosion of a metal surfaceprotectedis coated with themetal which is easily corrodible . (ii) The easily corrodiblemetal is called SACRIFICIAL metal to act as anodeensuring cathodicprotection .

Discussion

1262.	What is isomerism?
Answer» Solution :It is a phenomenon in which compounds have the same molecular formula but DIFFERENT STRUCTURAL formula.

Discussion

1263.	Which of the following is not an example of redox reaction?
Answer» `CuO+H_(2)toCu+H_(2)O` `Fe_(2)O_(3)+3COto2Fe+3CO_(2)` `2K+F_(2)to2KF` `BaCl_(2)+H_(2)SO_(4)toBaSo_(4)+2HCl` SOLUTION :`BaCl_(2)+H_(2)SO_(4)toBaSO_(4)+2HCl` is a PERCIPITATION reaction and is a non redox reaction.

Discussion

1264.	What are the methods used by plants to get rid of excretory products ?
Answer» Solution :Plants have COMPLETELY DIFFERENT strategies for excretion than those of animals They can get rid of excess water by transpiration. For other WASTES, plants use the fact that many of their tissues consists of dead cells and that they can even lose some parts such as leaves. In many plants waste products may be stored in leaves that all the waste products are stored as resins and gums. especially in old xylem. Plants also EXCRETE some waste substances into the soil around them.

Discussion

1265.	What is meant by reversible reaction ?
Answer» Solution :The reaction in which the REACTANTS have a tendency to FORM PRODUCTS while the products have a tendency to REFORM the reactants is called a reversible reaction.

Discussion

1266.	What is the common name of the compound CaOCl_2?
Answer» SOLUTION :BLEACHING POWDER.

Discussion

1267.	What are ionic compounds or electrovalent compounds ? Explain with example.
Answer» Solution :The compounds formed by the transfer of electrons from a metal to a non-metal are known as ionic compounds or electrovalent compounds. ATOMIC number of sodium is 11. Sodium atom has ONE electron in its outermost shell (M-shell). Sodium atom loses the electron from its M-shell and forms sodium CATION `(Na^+)`and acquires stable complete octet structure of noble gas neon (Ne). `underset(2,8,1)(Na) to underset(2,8)(Na^+) + e^-` Similarly, atomic number of chlorine is 17. Chlorine atom has seven electrons in its outermost shell (M-shell). Chlorine atom gains one e which is lost by sodium atom and forms chloride anion `(Cl^-)`and acquires stable complete octet structure of noble gas ARGON (Ar). `underset(2,8,7)(Cl)+ e^(-) to underset(2,8,8)(Cl^-)` Sodium cation `(Na^+) `and chloride anion `(Cl^-)`being oppositely charged attract each other and are held by strong ELECTROSTATIC forces of attraction and exists as sodium chloride (NaCl). Sodium chloride exists as a group of oppositely charged ions.

Discussion

1268.	Which of the following is true in the periodic table?
Answer» ATOMIC SIZE INCREASES from left to right across a period. Electron AFFINITY decreases on going down a group. METALLIC character decreases from left to right across a period. Electronegativity increases on going down a group. Solution :Metallic character decreases from left to right across a period.

Discussion

1269.	Thesymol ' amu ''u'denotesunified_______.
Answer» SOLUTION :ATOMICMASS

Discussion

1270.	Which of the following is not obtained on fractional distillation of petroleum?
Answer» PARAFFIN wax Asphalt COAL GAS Petroleum gas Solution :Coal gas

Discussion

1271.	Write two reasons responsible for late discovery of noble gases.
Answer» SOLUTION :(i) They are UNREACTIVE. (II) They have ZERO VALENCY.

Discussion

1272.	When ammonia reacts with hydrogen chloride gas, it produces white fumes of ammonium chloride. The volume occupied by NH_(3) in glass bulb A is three times more than the volume occupied by HCl in glass bulb B at STP. (i) How many moles of of ammonia are present in glass bulb A? (ii) How many grams of NH_(4)Cl will be formed when the stopper is opened? ("Atomic mass of N = 14, H = 1, Cl = 35.5") (iii) Which gas will remain after completion of the reaction? (iv) Write the chemical reaction involved in this process.
Answer» Solution :(i) `"Capacity of "NH_(3)" bulb = 67.2 litre"` `"22.4 litre of "NH_(3)="1 mole"` `therefore"67.2 litre of "NH_(3)=(1)/(22.4)xx67.2="3 moles of "NH_(3)` (ii)`{:("Atomic MASS of 1(N)"=1xx14,=,14g),("Atomic mass of 4(H)"=4xx1,=," 4g"),("Atomic mass of 1(Cl)"=1xx35.5,=,35.5g),(,,""ulbar("53.5g")):}` `"Mass of "NH_(4)Cl=53.5g` (iii) `NH_(3)` (Ammonia) gas will remain after the completion of the reaction. (iv) Chemical equation of the reaction `underset("Ammonia")(NH_(3))+underset("Hydrochloric ACID")(HCl)RARR underset("CHLORIDE")underset("Ammonium")(NH_(4)Cl)`

Discussion

1273.	Which of the following reaction occurs in whitewashing of walls ?
Answer» `2Ca+O_(2) to 2CaO` `CaO+ H_(2)O to CA(OH)_(2)+"HEAT"` `Ca(OH)_(2) +CO_(2) to CaCO_(3) +H_(2)O` `Ca(OH)_(2) OVERSET(Delta)to CaO+H_(2)O` Solution :`Ca(OH)_(2) +CO_(2) to CaCO_(3) +H_(2)O`

Discussion

1274.	Write next two members of the homologous series C_(2)H_(6),C_(3)H_(8).
Answer» Answer :`C_(4)H_(10),C_(5)H_(12).`

Discussion

1275.	To protect our teeth from decay, we should use toothpastes which are acidic.
Answer» SOLUTION : FALSE – TOOTHPASTES are BASIC.

Discussion

1276.	Where would you place the element with electronic configuration 2, 8 in the modern periodic table ?
Answer» GROUP 8 Group 2 Group 18 Group 10 Answer :A

Discussion

1277.	What is the nature of oxides formed by most of p - block elements ?
Answer» SOLUTION :ACIDIC OXIDES.

Discussion

1278.	Who proposed the 'Modern periodic law for the modern periodic table ?
Answer» Dobereiner Newlands HENRY Moseley Mendeleev

Discussion

1279.	What is the value of the ionic product of water at25^(@)C ?
Answer» SOLUTION :`10^(-14) MOL^(2) L^(-2)`

Discussion

1280.	The temperature at absolute zero is
Answer» `273.15^@C` `0^@C` `-373.15^@C` `-273.15^@C` ANSWER :D

Discussion

1281.	Which of the followiong substances is (are) obtained as by- product(s) during the preparation of sodium hydroxide by chlor-alkali process ?
Answer» Hydrogen sodium bicarbonate Common SALT Chlorine Answer :A::D

Discussion

1282.	What id precipitation reaction?
Answer» Solution :When aqueous solution of two compounds are MIXED ,if they react to FORM an insoluble compound and a soluble compound,then it is called precipitation reaction. e.g. `Pb(NO_(3))_(2(aq))+2Kl_((aq))toPbI_((s))darr+2KNO_(2(aq))`

Discussion

1283.	The tendency to gainelectron _____ on going from top to bottom in a group of the periodic table.
Answer» SOLUTION :DECREASES

Discussion

1284.	Which one of the following is used for makinfg pressrue cookers?
Answer» BRASS Magnalium Duralumin Nickel steel ANSWER :C

Discussion

1285.	Valency of Na (2,8,1) : 1 (One) : : Valency of P(2 , 8 , 5) :_________
Answer» Solution :3 (Three) - Na loses 1 electron to get the configuration of He (3b) and P REQUIRES 3 ELECTRONS to get a configuration 2,8,8. (Ar). Therefore, the valency of P is 3.

Discussion

1286.	Which metals react violently with cold water?
Answer» Solution :SODIUM and POTASSIUM METALS react violently with COLD WATER.

Discussion

1287.	The valences of zinc ion and phosphate ion are2^(+) and 3^(-)respectively . Write the formula of the compound formed when these two ions combine.
Answer» SOLUTION :`Zn_(3)(PO_(4))_(2)`

Discussion

1288.	What is the role of metal or reagents written on arrows in the given chemical reactions? (a) {:(CH_(3)),("\"),(""C),("/"),(CH_(3)):}=C{:(" CH"_(3)),("/"),("\"),(" CH"_(3)):}+H_(2) overset(Ni)toCH_(3)-underset(H)underset(\|)overset(CH_(3))overset(\|)C-underset(H)underset(\|)overset(CH_(3))overset(\|)C-CH_(3) (b) CH_(3)COOH+CH_(3)CH_(2)OH overset("Conc. "H_(2)SO_(4))to CH_(3)COOC_(2)H_(5)+H_(2)O (c ) CH_(3)CH_(2)OH underset("Heat")overset("Alk. "KMnO_(4))to CH_(3)COOH
Answer» SOLUTION :(a) Ni ACTS as a catalyst. (b) Concentrated `H_(2)SO_(4)` acts as a catalyst and a dehydrating agent. (c ) Alkaline `KMnO_(4)` acts as an oxidising agent.

Discussion

1289.	Writeequation for the reactions of (i) iron with steam (ii) calcium and potassium with water.
Answer» Solution :(i) Iron with steam:`4H_2O(g) + 3FE(s) to Fe_3O_4 + 4H_2(g)` (ii) calcium and potassium with WATER : `Ca(s) + underset("cold water")(2H_2O(l))to Ca (OH)_2 + H_2O (g) + ` heat ENERGY `2K(s) + underset("cold water")(2H_2O(l)) to 2KOH (AQ) + H_2(g) + `heat energy

Discussion

1290.	Write the balanced chemical equations for the following reaction : (i) Barium chloride + Potassium sulphate to Barium sulphate + Potassium chloride (ii) Zinc + Silver nitrate to Ainc nitrate + Silver
Answer» SOLUTION :(i) `BaCl_(2)+K_(2)SO_(4) to underset("(White ppt.)")underset("Barium sulphate")(BaSO_(4))+2KCl` (ii) `Zn+2AgNO_(3) to underset("NITRATE")underset("ZINC")(Zn(NO_(3))_(2))+2Ag`

Discussion

1291.	Which electronic configuration corresponds to a halogen?
Answer» 2, 2 `2, 8, 2` ` 2, 8, 1` `2, 8, 7` SOLUTION :`2, 8, 7`

Discussion

1292.	What is catenation?
Answer» Solution :Carbon has the ability to form covalent bonds with other atoms of carbon GIVING rise to a large number of MOLECULES through self linking property. This property is called CATENATION.

Discussion

1293.	What happens when calcium is treated with water ? (i) It does not react with water. (ii) It reacts violently with water. (iii) It reacts less violently with water. (iv) Bubbles of hydrogen gas formed stick to the surface of calcium.
Answer» (i) and (iv) (ii) and (III) (i) and (ii) (iii) and (iv) Solution :Calcium reacts comparatively less VIOLENTLY with water and floats on the surface DUE to HYDROGEN gas sticking to the surface of the metal.

Discussion

1294.	Which non-metal is a good conductor of electricity ?
Answer» SOLUTION :GRAPHITE.

Discussion

1295.	Write the chemical formulae of washing Soda. What happens when crystals of washing soda are exposed to air ?
Answer» Solution :(a) The loss of water of crystallisation from a hydrated salt when left open in air is called efflorescence. When crystals of washing soda,`Na_2CO_3 . 10H_2O`are left open in air they lose nine molecules of water of crystallisation and FORM MONOHYDRATE. This process is called efflorescence. `overset("Heat")to Na_2CO_3. H_2O + 9H_2O` (b) Important properties of washing soda . 1. Sodium carbonate is a transparent crystalline solid. It EXISTS as a decahydrate `(Na_2CO_3. 10H_2O)` containing 10 molecules of water of crystallisation . 2. It is readily soluble in water. It dissolves in water to form an alkaline solution, which turns red litmus solution blue. This shows that an aqueous solution of sodium carbonate is alkaline. 3. Action of heat. When crystals of washing soda are left open in air they lose nine molecules of water of crystallisation and form monohydrate. This process in known as efflorescence. Thus, washing soda is efflorescent. `underset("Sodium carbonate (decahydrate)")(Na_2CO_3. 10H_2O) underset("air) overset("EXPOSURE to ") tounderset("Sodium carbonate (monohydrate)")(Na_2CO_3. H_2O + 9H_2O)` On heating above 373 K, washing soda does not decompose but loses all its water of crystallisation to form anhydrous salt. Thus, the monohydrate becomes completely anhydrous and CHANGES to a white powder called soda ash.

Discussion

1296.	What type of system do you expect to obtain when finely powdered calcium carbonate is thoroughly stirred with water is a test tube ?
Answer» SOLUTION :The SYSTEM will be a SUSPENSION

Discussion

1297.	The variety of coal used as old house coal is
Answer» ANTHRACITE PEAT lignite BITUMINOUS SOLUTION :bituminous

Discussion

1298.	There was no place for __________ in Mendleev's orginal periodic table.
Answer» SOLUTION :NOBLE GASES

Discussion

1299.	What happens when dilute hydrochloric acid is added to iron filings? Choose the correct answer.
Answer» HYDROGEN GAS and iron chloride are produced Chlorine gas and iron hydroxide are produced No REACTION takes place Iron and water are produced Solution :The following reaction takes place: `underset("Iron")(Fe)+underset("HYDROCHLORIC acid")(2HCl)rarrunderset("Iron chloride")(FeCl_(2))+underset("Hydrogen")(H_(2))` Thus, hydrogen and iron chloride are produced.

Discussion

1300.	The secondary suffix used in IUPAC nomenclature of an aldehyde is………………
Answer» `- OL` `- IOC` ACID `- al` `- "one"` Solution :`-underset(O)underset(\|\|)(C)-H` (aldehyde group). Suffix .al. is USED to exhibit aldehyde group.

Discussion

Explore topic-wise InterviewSolutions in .

When reddish brown copper metal is heated it forms a black solid surface. Which of the following statement is incorrect ?

Write the formula used to determine the maximum numbers of electrons which a shell in an atom can accommodate.

What is the product [H^(+)] xx [OH^(-)] called ?

What is a balanced chemical equation? Why should the chemical equations be balanced?

When sodium chloride is dissolved in water the solution obtained is

Which of the following is acidic in nature ?

What is the common name of the elements of group 1?

Which of the following statements about the given reaction are correct ? 3Fe(s)+4H_(2)O(l)toFe_(3)O_(4)(s)+4H_(2)(g)

Which of the following statements is valid for a mixture ?

What are the methods preventing corrosion ?

What is isomerism?

Which of the following is not an example of redox reaction?

What are the methods used by plants to get rid of excretory products ?

What is meant by reversible reaction ?

What is the common name of the compound CaOCl_2?

What are ionic compounds or electrovalent compounds ? Explain with example.

Which of the following is true in the periodic table?

Thesymol ' amu ''u'denotesunified_______.

Which of the following is not obtained on fractional distillation of petroleum?

Write two reasons responsible for late discovery of noble gases.

Which of the following reaction occurs in whitewashing of walls ?

Write next two members of the homologous series C_(2)H_(6),C_(3)H_(8).

To protect our teeth from decay, we should use toothpastes which are acidic.

Where would you place the element with electronic configuration 2, 8 in the modern periodic table ?

What is the nature of oxides formed by most of p - block elements ?

Who proposed the 'Modern periodic law for the modern periodic table ?

What is the value of the ionic product of water at25^(@)C ?

The temperature at absolute zero is

Which of the followiong substances is (are) obtained as by- product(s) during the preparation of sodium hydroxide by chlor-alkali process ?

What id precipitation reaction?

The tendency to gainelectron _____ on going from top to bottom in a group of the periodic table.

Which one of the following is used for makinfg pressrue cookers?

Valency of Na (2,8,1) : 1 (One) : : Valency of P(2 , 8 , 5) :_________

Which metals react violently with cold water?

The valences of zinc ion and phosphate ion are2^(+) and 3^(-)respectively . Write the formula of the compound formed when these two ions combine.

Writeequation for the reactions of (i) iron with steam (ii) calcium and potassium with water.

Write the balanced chemical equations for the following reaction : (i) Barium chloride + Potassium sulphate to Barium sulphate + Potassium chloride (ii) Zinc + Silver nitrate to Ainc nitrate + Silver

Which electronic configuration corresponds to a halogen?

What is catenation?

What happens when calcium is treated with water ? (i) It does not react with water. (ii) It reacts violently with water. (iii) It reacts less violently with water. (iv) Bubbles of hydrogen gas formed stick to the surface of calcium.

Which non-metal is a good conductor of electricity ?

Write the chemical formulae of washing Soda. What happens when crystals of washing soda are exposed to air ?

What type of system do you expect to obtain when finely powdered calcium carbonate is thoroughly stirred with water is a test tube ?

The variety of coal used as old house coal is

There was no place for __________ in Mendleev's orginal periodic table.

What happens when dilute hydrochloric acid is added to iron filings? Choose the correct answer.

The secondary suffix used in IUPAC nomenclature of an aldehyde is………………