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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1051. |
This process of changing of solid state into liquid state is called |
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Answer» Fusion |
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| 1052. |
Write short note on electrolytic refining of metals. |
Answer» Solution :In electrolytic refining, IMPURE METAL is made anode and a thin wire of pure metal is made cathode. Solution of metal salt in WATER acts as the ELECTROLYTE. On passing metal from anode gets oxidised and enters the solution as cations. The cations near cathode get reduced and deposit at cathode in the form of pure metal. The impurities are collected at the bottom, below the anode. Those are known as anode mud. The PROCESS is shown in the following diagram. 
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| 1053. |
Write word - equations and then balanced equations for the reactions taking place when (a) dilute sulphuric acid reacts with zinc granules. (b) dilute hydrochloric acid reacts with magnesium ribbon. (c) dilute sulphuric acid reacts with aluminium powder. (d) dilute hydrochloric acid reacts with iron filings. |
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Answer» Solution :(a) Sulphuric acid (aq) + Zinc (s) `rarr` Zinc sulphate(aq) + Hydrogen (g) `H_(2)SO_(4) (aq) rarr Zn(s) rarr ZnSO_(4) (aq) + H_(2)(g)` (b) Hydrochloric acid (aq) + Magnesium (s) `rarr` Magnesium chloride (aq) + Hydrogen(g) `2HCl(aq) +MG(s)rarr MgCl_(2)+ H_(2) (g)` (c) Sulphuric acid + Aluminium (s) `rarr` Aluminium sulphate (aq) + Hydrogen (g) `3H_(2) SO_(4) +2Al(s) (SO_4)_(3) (aq) +3H_(2)(g)` (d) Hydrochloric acid (aq) + Iron(s) `rarr` Iron chloride (aq) + Hydrogen (g) `2HCl(aq) + FE(s) rarr FeCl_(2) (aq) + H_(2)(g)` |
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| 1054. |
what are F-centres |
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Answer» ANIONIC sites OCCUPIED by unpaired electrons |
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| 1055. |
What is roasting in metallurgy ? |
| Answer» Solution :The sulphide ORES are converted into OXIDES by HEATING strongly in the PRESENCE of EXCESS air. | |
| 1057. |
What change will you observe if you test soap with litmus paper (red or blue)? |
| Answer» Solution :A soap is the salt of a strong BASE (sodium hydroxide) and a weakacid (carboxylic ACID), so a solution of soap in water is BASIC in nature. Being basic, a soap solution will turn red litmus paper BLUE. | |
| 1058. |
Write the number of horizontal rows in the modern periodic table. What are these rows called ? |
| Answer» SOLUTION :The number of horizontal rows in the periodic table is 7. These rows are CALLED PERIODS. | |
| 1059. |
Write the balanced chemical equations for the following reactions : Amuminium + Copper chloride to Aluminium chloride + Copper |
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Answer» SOLUTION :BALANCED CHEMICAL EQUATIONS for the reactions are GIVEN as under : `2Al+3CuCl_(2)to2AlCl_(3)+3Cu` |
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| 1060. |
Zn^(+2) and Ag^(+) are present in a solution to be electrolysed. The metal that is deposited first at cathode is ______ |
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Answer» |
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| 1061. |
Thermal Decompositionreaction: Thermolysis:: electrolyticDecompositionReaction:_______. |
| Answer» SOLUTION :ELECTROLYSIS | |
| 1062. |
Water is neutral of litmus paper. This is because in water ? |
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Answer» `[H^(+)] gt [ OH^(-)]` |
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| 1063. |
Which element exhibits the property of catenation ? Why ? |
| Answer» Solution :CARBON atom has a smaller size and hence can hold on to the SHARED pair of electrons [in BONDS] strongly. Hence the COMPOUNDS of carbon are very STABLE. | |
| 1064. |
Write the name and the structure of an aldehyde with four carbon atoms in its molecule |
Answer» SOLUTION :
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| 1065. |
The size of a cation is always __________ thanits correspondingneutral atom. |
| Answer» SOLUTION :SMALLER | |
| 1066. |
Which of the gases present in air is most effective in causing greenhouse effect ? |
| Answer» SOLUTION :CARBON DIOXIDE (`CO_(2)` | |
| 1067. |
Write the chemical formula of washing soda. How is it obtained from baking soda ? Name one use of washing soda, other than washing clothes. |
| Answer» SOLUTION :`Na_(2)CO(3)` | |
| 1068. |
Which one of the following solutions with same concentrations is most basic? |
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Answer» `NaHCO_(3)` |
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| 1069. |
Which gas is collected in a test tube at anode as shown in figure ? |
| Answer» SOLUTION :OXYGEN GAS | |
| 1070. |
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions. |
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Answer» Solution :In a COMBINATION reaction, two or more substances combine to form a single product. Also, a large amount of heat is evolved. The DECOMPOSITION reactions REQUIRE energy either in the form of heat, light or electricity for BREAKING down one substance into two or more substances. `N_(2)+3H_(2)rarr2NH_(3)+"Heat"`, Combination reaction `2NH_(3)+"Heat"rarrN_(2)+3H_(2)`, Decomposition reaction |
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| 1071. |
Which of the following is a dibasic acid? |
| Answer» Solution :NA | |
| 1072. |
Write the condensed formula and structural formula of acetic acid. What is its IUPAC name? |
| Answer» SOLUTION : CONDENSED FORMULA = `CH_3COOH`, Structural formula is `underset("(Ethanoicacid )")(H-underset(H) underset(|)OVERSET(H)overset(|)C - overset(O ) overset(||)C-O -H)` | |
| 1073. |
What is meant by isomers ? Draw the structure of two isomers of butane, C_(4)H_(10). Explain why we cannot have isomers of first three members of alkane series. |
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Answer» Solution :Isomers are the compounds which have the same molecular FORMULA but different structural formula. Isomers of Butane: `H-underset("n-butane")(underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)H)` (II) `H-underset(|)overset(H)overset(|)(C)-H` `H--underset(H)underset(|)overset(H)overset(|)(C)--underset(H)underset(|)overset(H)overset(|)(C)--underset(H)underset(|)overset(H)overset(|)(C)H` We cannot have isomers of the first three members of the alkane series because of the following LAWS of isomers : (i) The parent chain should have the most number of carbon atoms. (ii) The branching cannot be done from the first on the LAST ATOM carbon atom of the structure. |
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| 1074. |
Which nonmetal is octatomic? |
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Answer» Helium |
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| 1075. |
When hydrogen sulphide is treated with chlorine gas, it gives hydrochloric acid and sulphur precipitates out. The type oof chemical reaction involved is |
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Answer» combination REACTION |
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| 1076. |
What is an aqua regia ? |
| Answer» SOLUTION :A freshly prepared MIXTURE of CONCENTRATED hydrochloric acid and concentrated nitric acid in the ratio of 3:1 by VOLUME is called an aqua regia. | |
| 1077. |
Zinc reacts with sulphuric acid to form zinc sulphate with liberation of ________ gas. |
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Answer» Solution :hydrogen. The reaction that TAKES PLACE is : `Zn+H_(2)SO_(4)toZnSO_(4)+H_(2)` |
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| 1078. |
Write the name and structure of an aldehyde with four carbon atoms in its molecule. |
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Answer» Solution :Butanal, `CH_(3)-CH_(2)-CH_(2)-CHO` or `H-UNDERSET(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-overset(O)overset(||)C-H` |
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| 1079. |
Which of the following statements about the dissolution of ammonium chloride in water is (are) correct ? |
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Answer» the temperature of the SOLUTION increases. |
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| 1080. |
Which of the following is least compressible? |
| Answer» Solution :solid | |
| 1081. |
Which of the following is incorrect ? |
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Answer» COBALT oxide imparts blue COLOUR to glass |
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| 1082. |
Wrought iron is more malleable than cast iron. Give reason. |
| Answer» SOLUTION :Wrought iron is the PUREST FORM of iron. Its carbon content is the LEAST. Hence, it is highly MALLEABLE. | |
| 1083. |
Which of the following is used in a chemical reaction with HCl and leads to the evolution of a gas? |
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Answer» ZINC granules |
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| 1084. |
Which of the following is not balanced equation? |
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Answer» `Ca(HO)_(2) + CO_(2) to CaCO_(3) + H_(2)O` |
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| 1085. |
Though sulphur has only two unpaired electrons it exhibits covalency of 2, 4, 6. Explain. |
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Answer» Solution :(i) valence shell of 'S'. (ii) number and TYPE of orbitals present in the valence shell (III) number of unpaired and paired ELECTRONS present in valence shell in ground state (iv) number of unpaired electrons possible in different exited STATES (v) relation between number of unpaired electrons and COVALENCY |
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| 1086. |
Which chemicals are used in soda-acid fire extinguishers ? |
| Answer» SOLUTION :SODIUM hydrogenecarbonate `(NaHCO_3)` and SULPHURIC and `(H_2SO_4)`. | |
| 1087. |
The sum of the number of protons and neutrons of an atom is called its ……….. |
| Answer» Solution :mass number | |
| 1088. |
What is the value of ionic product of water? |
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Answer» `1XX10^(-4)` |
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| 1089. |
Write the formula and chemical name of bleaching powder. |
| Answer» Solution :FORMULA of BLEACHING powder is `CaOCl_2`, and the chemical NAME is CALCIUM OXYCHLORIDE. | |
| 1090. |
When a white crystalline solid is heated strongly, it decomposes to gives a yellow residue, reddish brown gas, and rekindles a glowing splinter. Identify the reddish - brown gas. |
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Answer» OXYGEN |
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| 1091. |
Who modified Bohr's theory of introducing elliptical orbits for electron path? |
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Answer» Hund |
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| 1093. |
Write the balanced chemical equation for the reaction that takes place during respiration. Identify the type of combination reaction that taken place during this process and justify the name. Give one more example for this type of reaction. |
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Answer» Solution :The balanced chemical equation is `C_(6)H_(12)O_(6)(aq)+6O_(2)(g)to6CO_(2)(g)+6H_(2)O(l)+"heat"` It is an exothermic combination reaction because heat is evolved. COMBUSTION of methane is another example for exothermic combination reaction : `CH_(4)(a)+2O_(2)(g)toCO_(2)(g)+2H_(2)O(l)`. |
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| 1094. |
What is sublimation? |
| Answer» Solution :It is PROCESS by which a solid on HEATING DIRECTLY changes into vapour. And the vapour on COOLING changes back into the solid. | |
| 1095. |
Why are soaps not suitable for washing clothes with hard water? |
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Answer» Solution :Soaps are not suitable for washing clothes with hard water because of two reasons: (i) Soap reacts with the calcium and magnesium ions PRESENT in hard water to form INSOLUBLE precipitate called scum. This results in the WASTAGE of soap. (ii) The sicky scum sticks to the clothes being washed and interferes with the cleaning ABILITY of soap. This MAKES the cleaning of clothes difficult. |
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| 1096. |
Which among the following reactions is an example of instantaneous reaction under normal conditions ? |
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Answer» `2H_(2) + O_(2) to 2H_(2)O` |
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| 1098. |
What change is noticed in the electrolyte ?During the electrolysis of copper (II) sulphate solution using platinum as cathode and carbon as anode: |
| Answer» SOLUTION :BLUE of COLOUR FADES | |