8881 + Interview Questions in Chemistry in Class 10 Page 17 InterviewSolution

801.	Write the name and formula of the 2^(nd) member of homologous series having general formula C_(n)H_(2n+2).
Answer» ANSWER :Name : ETHANE Formula `C_(2)H`

Discussion

802.	When a strip of copper is introduced in a solution of zinc sulphate , zinc is precipitated.
Answer» ANSWER :T

Discussion

803.	Write the chemical equation involved in the following chemical reactions: (i) White washing. (ii) Black and white photography.
Answer» Solution :(i) In white washing, QUICKLIME REACTS with water to from slakedlime. `underset("Quick LIME")(CaO+H_(2)O) rarr underset ("Slacked lime")(Ca(OH)_(2)+"Heat")` (ii)Silver bromide, when exposed to light decomposes toto silver and bromine. `underset ("Silver bromide")(2AgBr(s)) overset ("SUNLIGHT") rarr underset("Silver")(2Ag(s))+ underset("Bromine")(Br_(2)(g))`

Discussion

804.	Which among the following metals is not present in german silver?
Answer» Cu AG Zn Ni Solution :Ag is not PRESENT in GERMAN SILVER.

Discussion

805.	What type of chemical reactions are represented by the following equations? (i) A+BrarrC (ii) A+BCrarrAC+B (iii) ArarrB+C (iv) AB+CDrarrAD+BC
Answer» Solution :(i) Combination REACTION (II) DISPLACEMENT reaction (iii) Decomposition reaction (iv) DOUBLE displacement reaction

Discussion

806.	Which of the following non metal is good conductor of electricity .
Answer» Graphite Phosphorous Hydrogen Bromine Answer :A

Discussion

807.	Use your brain power, What is the expected trend in the variation of non-metallic character of element from left to right in a period?
Answer» SOLUTION :Non-metallic character INCREASES from LEFT to right in a PERIOD.

Discussion

808.	The slow chemical change that takes place in complex organic compounds by the action of…………………..leading to the formation of simple molecules is called………………….
Answer» SOLUTION :ENZYMES, fermentaion

Discussion

809.	What is the significanceof modern periodic table ?
Answer» Solution :(i) The main significanceof MODERN periodic table is its GIVES a clearunderstanding ofthe general PROPERTIESAND trends within a GROUP ora period. (ii) To predictwith accuracy the propertiesof any ELEMENT .

Discussion

810.	Which scientist proposed the periodic law for the modern periodic table ?
Answer» SOLUTION :HENRY MOSELEY

Discussion

811.	Which of the following is more reactive than Cu according to the reactivity series
Answer» Hg Ag Na Au Answer :C

Discussion

812.	Two substances X and Y are dissolved in water under suitable conditions. X is a gas while Y is a solid under normal conditions. Solution of Y is found to conduct electricity but not 'X'.Based on the conclusion identify the nature of bond present in X and Y with appropriate reasons as given below. Arrange the steps given below in a sequence. (1) Y is a solid at room temperature and its aqueous solution conducts electricity. This shows that it is an ionic compound. (2) X on dissolution in water does not conduct electricity and is a gas at room temperature. Hence it should be a non-polar covalent molecule. (3) Aqueous solutions of both ionic compounds and polar covalent compounds conduct electricity because of the presence of free ions. (4)All ionic compounds are solids and most of the non-polar covalent molecules are gases or solids at room temperature. Polar covalent compounds are liquids or gases.
Answer» 3 4 2 1 1 4 3 2 1 3 2 4 3 1 2 4 Solution :(i) Aqueous SOLUTIONS of both ionic COMPOUNDS and polar covalent compounds conduct electricity because of the presence of free ions. (ii) All the ionic compounds are SOLIDS and most of the non-polar covalent molecules are gases or solids at room temperature. Polar covalent compounds are LIQUIDS or gases. (iii)As aqueous solution of X doesn't conduct electricity and moreover it is a gas at roo, temperature. It should be a non-polar molecule. Hence, it is a covalent molecule. (iv) Y is a solid at room temperature in which its aqueous solution conducts electricity shows that it is an ionic compound.

Discussion

813.	Which of the following melts at a certain temperature ?
Answer» Gun powder An MIXTURE of IRON and SULPHUR SODIUM chloride A mixture of sand and sugar Answer :C

Discussion

814.	Write the balanced chemical equation for thereactions : Calcium hydroxide + Carbon dioxide to Calcium carbonate + Water
Answer» Solution :`underset("CALCIUM hydroxide")(Ca(OH)_(2)(aq))+ underset("Calcium dioxide")(CO_(2)(G)) to underset("Calcium carbonate")(CaCO_(3)(s))+ underset("WATER")(H_(2)O(I))`

Discussion

815.	Whenever a ________ change occurs, we say that a chemical reaction has taken place.
Answer» SOLUTION :CHEMICAL

Discussion

816.	What is the difference between the molecules of soaps and detergents, chemically ? Explain the deansing action of soaps.
Answer» Solution :Detergents are sodium salt of long chain benzene sulphonic acids. Soaps are sodium or potassium salt of long chain fatty acids that have cleaning action in water. e.g., Sodium stearate. Cleansing Addion of Soap. A soap molecule consists of two dimilar parts : (i) A short ionic part comprising the carboxylate salt--`COO^(-)Na^(+)` which is water soluble. (ii) A long hydrocarbon chain which is HYDROPHOBIC. When soap is dissolved in water, it FORMS a colloidal SUSPENSION. In this colloidal suspension, the soap MOLECULES duster together to form micelles and remain radially SUSPENDED in water with the hydrocarbon end towards the centre and the ionic end directed outward. The dirt particles always adhere to the oily or greasy layer present on the skin or clothes. When a dirty cloth is dipped into a soap solution, its non-polar hydrocarbon end of micelles gets attached to the grease or oil present in dirt and polar end remains in water layer. The mechanical action of rubbing subsequently, dislodges the oily layer from the dirty surface shaping it into small globules. A stable emulsion of oil in water is formed. The emulsified oil or grease globules bearing the dirt can now! eadily washed with water.

Discussion

817.	When aqueous solution of silver niotrate and sodium chlorid are mixed,…….precipitate is immediately formed.
Answer» White Yellow Red Black

Discussion

818.	The tip of the lead pencil is made of
Answer» LEAD GRAPHITE zinc charcoal ANSWER :B

Discussion

819.	Translate the following statements into chemical equations and then balance them : Hydrogen sulphide gas burns in air to give water and sulphur dioxide.
Answer» Solution :`underset("(from AIR)")(H_(2)S(G)+O_(2)(g)toH_(2))O(l)+SO_(2)(g)"(UNBALANCED EQUATION)"` `2H_(2)S(g)+3O_(2)(g)to2H_(2)O(l)+2SO_(2)(g)"(Balanced equation)"`

Discussion

820.	Write the molecular formula and electron dot structure of a] Ethane "" b] Ethyne
Answer» SOLUTION :

Discussion

821.	The separationn of one lanthanide from another is an extremely difficult task, almost as difficult as the separation of isotopes of one element. Justify.
Answer» Solution :(i) differentiating electron of lanthanides (ii) lanthanide contraction and its EFFECT on atomic and IONIC sizes of lanthanide ELEMENTS (iii) dependence ofchemical properties on the atomic sizes (iv) properties exploited for separation of different elements

Discussion

822.	Two salts are dissolved in water separately. When phenolphthalein is added to the two solutions, one solution turned pink and the other solution was colourless. How do you justify this ?
Answer» SOLUTION :(i) nature of solution where phenolphthalein is pink and colourless. (ii) nature of the comonents PRODUCED on hydrolysis of salts (III) relation between the COMPONENTS produced and the colour CHANGE of indicator

Discussion

823.	Wave nature of matter is applicable only for sub- atomic particles and not for larger objects. justify this statement.
Answer» Solution :(i) de BROGLIE wave EQUATION relation between mass and WAVELENGHT relation between wavelenght and NATURE of light

Discussion

824.	Write the main products in the reaction CH_3CH_2COONa + NaOH overset("CaO/heat")(to)
Answer» SOLUTION :`C_2H_6`

Discussion

825.	Transition elements : _________ :: Inner transitionelements: Three incomplete outermost shells
Answer» Solution :TWO incomplete outermost shells - The d-blockelemen t s have 2 incomplete outer most shellswhereas the f-block elements have 3 OUTERMOSTSHELL s which are incomplete.

Discussion

826.	The valency of copper in CuSO_(4)*5H_(2)Ois
Answer» 1 3 2 0 Answer :C

Discussion

827.	What is a metallic bond ?
Answer» Solution :The force that HOLDS the CLOSELY TOGETHER in a METAL is known as the metallic bond.

Discussion

828.	Which of the following natural materials act as acid-base indicators ?
Answer» RED cabbage LEAVES Geranium Hydrangea All the above Solution :All the three substances CHANGE colour in acidic and BASIC media.

Discussion

829.	Which substance becomes incandescent when heated in an oxyhydrogen flame ?
Answer» SOLUTION :CALCIUM OXIDE (CAO).

Discussion

830.	What is meant by the term pH of a solution? The pH of rain water collected from two cities A and B was found to be 6 and 5 respectively. The water of which city is more acidic?
Answer» SOLUTION :PH of a solution is a measure of the `H^+` ION concentration in a solution. Lesser the pH , more ACIDIC is the solution. Thus, rain water of city B is more acidic.

Discussion

831.	Write the number of periods the Modern Periodic Table has. State the changes in valency andmetallic character of elements as we move from left to right in a period. Also state the changes, ifany, in the valency and atomic size of elements as we move down a group.
Answer» SOLUTION :The Modern PERIODIC Table has 7 periods. Valency across a period INCREASES from 1 to 4, thendecreases from 4 to zero. METALLIC character of elements across a period decreases. Valency down a GROUP remains the same. Atomic size of elements down a group increases.

Discussion

832.	What product is formed ions can turn red litmussolution blue ?
Answer» HYDROCHLORIC ACID Carbonic acid CARBOLIC acid Malic acid ANSWER :C

Discussion

833.	Two metals X and Y form the salts XSO_(4) and Y_(2)SO_(4) respectively.The solution of salt XSO_(4) is blue in colour whereas that of Y_(2)SO_(4) is formed alongiwth a salt Which turns the solution green. And when barium chloride solution is added to Y_(2)SO_(4) solution, then the same white precipitate Z is formed alongwith colourless common salt solution. (a) What could the metal X and Y be ? (b) Write the name and formula of salt XSO_(4) (c) Write the name and formula of salt Y_(2)SO_(4) (d)What is the name and formula of white precipate Z ? (e) Write the name and formula of the salt which turns the solution green in the first case.
Answer» Solution :(a) The available information suggests that metals X and Y are COPPER (Cu) and SODIUM (Na) respectively. (b) The salt X is `CuSO_(4)` and its aqueous solution in BLUE in colour. (c) The salt Y is `Na_(2)SO_(4)` and its aqueous solution is colourless. (d) When `BaCl_(2)` solution is added to `CuSO_(4)` solution, a white precipitate of `BaSO_(4)` (Z) is formed. The solution acquires greenish colour due to formation of `underset((X))(CuSO_(4)) + BaCl_(2) to underset("White PPT (z)")(BaSO_(4)) + underset("Greenish solution")(CuCl_(2))` (e) The green solution as stated above is of cupric chloride.

Discussion

834.	Which of the following reaction will never occur
Answer» `CU + H_2 SO_4 to CuSO_4 + H_2` `MG + H_2 SO_4 to MgSO_4` `2AL + 6HCL to 2AlCl_3 + 3H_2` `Fe + 2HCl to FeCl_2 + H_2` Solution :`Cu + H_2 SO_4 to CuSO_4 + H_2`

Discussion

835.	ZnO is white at room temperature but turns yellow on heating due to
Answer» ANIONIC vacancies Extra CATION in INTERSTITIAL sites Frenkel defect F centre Answer :B

Discussion

836.	When 1 mole of the substance present in 1 L of solution is known as
Answer» normal solution molar solution molal solution none of these Solution :Molarity is a METHOD to express concentration of solution. It is defined as the NUMBER of MOLES of SOLUTE dissolved per LITRE of solution.

Discussion

837.	Write the name of the compound having the following formula:CH_3 - CH_2 - CH_2 - CH_2 - CH_3
Answer» Solution : IUPAC parts of the complete name of the structural formula: Root word, Primary suffix, SECONDARY suffix, Prefix. (i) There are 5 C atoms in the chain. Therefore, root word = pent. (1) Only C-C covalent bonds are present in the chain. Therefore, primary suffix is ane. (iii) There is no FUNCTIONAL group and substituent with the parent chain. Therefore, secondary suffix and prefix are not involved. Thus the IUPAC name of the given compound is DERIVED as: Root word + Primary suffix Pent + ane = Pentane

Discussion

838.	What is glycerol?
Answer» Solution :Giycerol is a sweet viscous LIQUID soluble in WATER .It is a BYPRODUCT of saponification process .It goes by a common name glycerie .It formula is `CH_(2)OH.CHOH.CH_(2)OH`.It is used in the manufature of explosives ,plastic and pharmaceuticals it is also used to prevent FREEZING .

Discussion

839.	Which gas burns with popping sound ?
Answer» Solution :Hydrogen GAS `(H_(2)(G))`

Discussion

840.	Which one of the following is least reactive element?FClBrI
Answer» F Cl Br I Solution :I

Discussion

841.	Which of the following pairs will give displacement reactions?
Answer» Solution :(d) Only COPPER (CU) will give DISPLACEMENT REACTION with `AgNO_(3)` solution because copper is placed above silver in the ACTIVITY series.

Discussion

842.	What is bleaching powder? How is it prepared? List two uses of bleaching powder.
Answer» Solution :Bleaching power is calcium oxychloride. It is prepared by the action of chlorine on dry SLAKED lime. `Ca(OH)_2+Cl_2 to CaOCl_2+H_2O` Bleaching powder Uses: (i) Used for bleaching cotton and linen in the TEXTILE industry and wood pulp in PAPER industry ETC. (i) It is used for disinfecting the drinking water.

Discussion

843.	Which of the following pairs will give displacement reaction?NaCl solution and copper metal,MgCl_2 solution and aluminium metal,FeSO_4 solution and silver metal,AgNO_3 solution and copper metal.
Answer» NaCl solution and copper METAL `MgCl_2` solution and ALUMINIUM metal `FeSO_4` solution and SILVER metal `AgNO_3` solution and copper metal. Solution :`AgNO_3` solution and copper metal.

Discussion

844.	What changes are observed when a soap solution is tested with a red and a blue litmus paper ?
Answer» SOLUTION :Soap solution is BASIC in nature. So, it will render a RED LITMUS paper blue, but it will not affect a blue litmus paper.

Discussion

845.	Write the steps for balancing the chemical quation for the formation of ammonia by the combination of nitrogen and hydrogen.
Answer» Solution :`Na+H_(2)rarrNH_(3)` (Unbalanced equation) (i) Examine the number of ATOMS of different elements present in the unbalanced equation. (ii) In the above reaction, N and H of both the SIDES are unbalanced. (III) To balance hydrogen, `H_(2)` is multipled by 3. It makes 6H-atoms on the left hand side. (IV) Now to balance hydrogen atoms on the righthand side, `NH_(3)` should be multiplied by 2. It makes 6H-atoms on this side (v) Now to balance nitrogen atoms, they are counted separately for both the side and we will FIND that, nitrogen atoms are 2 on both the sides. (vi) Balanced chemical equation will be : `N_(2)+3H_(2) rarr2NH_(3)`

Discussion

846.	Which of the following is not represents ketones?
Answer» `-C=O` `OH` `-CHO` `-COOH` ANSWER :A

Discussion

847.	Which of the following remains undissolved when treated with water ?
Answer» WASHING SODA Common salt Sand SUGAR Answer :C

Discussion

848.	ZnCO_3, Al_2O_3 * 2H_2O, CaCO_3, FeCO_3 .
Answer» SOLUTION :`Al_2O_3 *2H_2O`

Discussion

849.	Why are group 1 elements called alkali metals?
Answer» GROUP 1 Group 2 Group 17 Group 18 Answer :A

Discussion

850.	Why are sodium and potassium not usedto prepare hydrogen gas in the laboratory ?
Answer» SOLUTION :This is because the REACTION of sodium or potassium with acids is vigorousand highly EXOTHERMIC (heat GENERATING ). So, the reaction MAY occur with explosion.

Discussion

Explore topic-wise InterviewSolutions in .

Write the name and formula of the 2^(nd) member of homologous series having general formula C_(n)H_(2n+2).

When a strip of copper is introduced in a solution of zinc sulphate , zinc is precipitated.

Write the chemical equation involved in the following chemical reactions: (i) White washing. (ii) Black and white photography.

Which among the following metals is not present in german silver?

What type of chemical reactions are represented by the following equations? (i) A+BrarrC (ii) A+BCrarrAC+B (iii) ArarrB+C (iv) AB+CDrarrAD+BC

Which of the following non metal is good conductor of electricity .

Use your brain power, What is the expected trend in the variation of non-metallic character of element from left to right in a period?

The slow chemical change that takes place in complex organic compounds by the action of…………………..leading to the formation of simple molecules is called………………….

What is the significanceof modern periodic table ?

Which scientist proposed the periodic law for the modern periodic table ?

Which of the following is more reactive than Cu according to the reactivity series

Which of the following melts at a certain temperature ?

Write the balanced chemical equation for thereactions : Calcium hydroxide + Carbon dioxide to Calcium carbonate + Water

Whenever a ________ change occurs, we say that a chemical reaction has taken place.

What is the difference between the molecules of soaps and detergents, chemically ? Explain the deansing action of soaps.

When aqueous solution of silver niotrate and sodium chlorid are mixed,…….precipitate is immediately formed.

The tip of the lead pencil is made of

Translate the following statements into chemical equations and then balance them : Hydrogen sulphide gas burns in air to give water and sulphur dioxide.

Write the molecular formula and electron dot structure of a] Ethane "" b] Ethyne

The separationn of one lanthanide from another is an extremely difficult task, almost as difficult as the separation of isotopes of one element. Justify.

Two salts are dissolved in water separately. When phenolphthalein is added to the two solutions, one solution turned pink and the other solution was colourless. How do you justify this ?

Wave nature of matter is applicable only for sub- atomic particles and not for larger objects. justify this statement.

Write the main products in the reaction CH_3CH_2COONa + NaOH overset("CaO/heat")(to)

Transition elements : _________ :: Inner transitionelements: Three incomplete outermost shells

The valency of copper in CuSO_(4)*5H_(2)Ois

What is a metallic bond ?

Which of the following natural materials act as acid-base indicators ?

Which substance becomes incandescent when heated in an oxyhydrogen flame ?

What is meant by the term pH of a solution? The pH of rain water collected from two cities A and B was found to be 6 and 5 respectively. The water of which city is more acidic?

Write the number of periods the Modern Periodic Table has. State the changes in valency andmetallic character of elements as we move from left to right in a period. Also state the changes, ifany, in the valency and atomic size of elements as we move down a group.

What product is formed ions can turn red litmussolution blue ?

Which of the following reaction will never occur

ZnO is white at room temperature but turns yellow on heating due to

When 1 mole of the substance present in 1 L of solution is known as

Write the name of the compound having the following formula:CH_3 - CH_2 - CH_2 - CH_2 - CH_3

What is glycerol?

Which gas burns with popping sound ?

Which one of the following is least reactive element?FClBrI

Which of the following pairs will give displacement reactions?

What is bleaching powder? How is it prepared? List two uses of bleaching powder.

Which of the following pairs will give displacement reaction?NaCl solution and copper metal,MgCl_2 solution and aluminium metal,FeSO_4 solution and silver metal,AgNO_3 solution and copper metal.

What changes are observed when a soap solution is tested with a red and a blue litmus paper ?

Write the steps for balancing the chemical quation for the formation of ammonia by the combination of nitrogen and hydrogen.

Which of the following is not represents ketones?

Which of the following remains undissolved when treated with water ?

ZnCO_3, Al_2O_3 * 2H_2O, CaCO_3, FeCO_3 .

Why are group 1 elements called alkali metals?

Why are sodium and potassium not usedto prepare hydrogen gas in the laboratory ?