8881 + Interview Questions in Chemistry in Class 10 Page 42 InterviewSolution

2051.	What happens when bromine water is added to ethene gas?
Answer» Answer :Ethene GAS decolourises the BROWN colour of BROMINE WATER.

Discussion

2052.	What will be the pH of solution which turns red litmus Blue ?
Answer» 1 15 10 4 Solution :10

Discussion

2053.	while eating food, you spillsome curry on your shirt. You immediately scrub with soap, what happens to its yellow colour on scrubbing with soap ? What happens to the stain when the shirt is washed with plenty of water ?
Answer» SOLUTION :On SCRUBBING with soap, its yellow colour changes to reddish brown. It happens because soap is basic in nature and the colour of turmeric changes from yellow to reddish brown. When the shirt is washed with PLENTY of WATER,the STAIN turns yellow again.

Discussion

2054.	List the points of differences between homogeneous and heterogenous mixtures.
Answer» SOLUTION :A homogeneous mixture is ONE in which the COMPOSITION of the COMPONENTS is the same throughout the BODY the composition of the components is not same throughout.

Discussion

2055.	Why are decomposition reactions called the opposite of combination reactions ? Write equations for these reactions.
Answer» Solution :In DECOMPOSITION reaction, a single molecule of reactant by absorbing heat is broken down into two or more products (atoms), while in combination reaction, opposite phenomenon to decomposition reaction is observed. In combination reaction, two or more substances (ELEMENTS or compounds) combine to FORM a single product with heat change. Decomposition REACTIONS : AB + Energy `to` A + B `2AgCl(s) underset("Sunlight")to 2Ag(s) + Cl_(2)(g)` Combination reactions : A + B`to ` AB+Energy `C(s)+O_(2)(g) to CO_(2)+"Energy"`

Discussion

2056.	Which is state function ?
Answer» Q W `q + w (d)` NONE of these Answer :D

Discussion

2057.	When copper carbonate is heated ,the products formed are………….,…………….and change of colour from…….to ………………..is observed.
Answer» SOLUTION :CuO,`CO_(2)`,green,BLACK

Discussion

2058.	Which one of the following is an alkali metal?
Answer» a)Mg b)Al c)K d)Kr Solution :K

Discussion

2059.	To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is
Answer» a)acidic b)neutral c)BASIC d)corrosive Solution :basic

Discussion

2060.	Which elements have the largest and the smallest atoms?
Answer» Solution :Lithium (LI) has the LARGEST and OXYGEN (O) has the smallest atoms.

Discussion

2061.	What do you understand by the term natural selection?
Answer» Solution :According to THEORY of NATURAL SELECTION, nature SELECTS fittest animal. Animals which are not fit are eliminated by nature itself.

Discussion

2062.	X belongs to IA or 1^(st) group and 5^(th) period and Y succeeds X in the group. Z succeeds Y in the period. Arrange the following statements in the correct sequence in order to arrange X,Y and Z in the increasing order of their atomic sizes. (1) Effect of number of valence electrons and number of shells on the atomic size. (2) Identification of the elements X,Y and Z. (3) Determination of the number of shells and the number of valence electrons present in X, Y and Z. (4) Determination of the positionns of Y and Z in the periodic table based on the position of X.
Answer» (a) 4 2 3 1 (b) 2 4 3 1 (c) 3 1 4 (d) 4 3 1 Solution :(1) Determination of the positionns of Y and Z in the PERIODIC table based on the position of X. . (2) Determination of the number of shells and the number of valence electrons present in X, Y and Z. (3) Effect of number of valence electrons and number of shells on the atomic size.

Discussion

2063.	Which of the compounds has an aldehyde group ?
Answer» `C_5H_8O` `C_5H_12O` `C_5H_10O` `C_5H_9O` ANSWER :C

Discussion

2064.	Write the balanced chemical equation for the following chemical reactions. Sodium hydroxide solution is treated with acetic acid to form sodium acetate and water.
Answer» Solution :`NAOH(aq.)+CH_(3)COOH(aq.)toCH_(3)COONa(aq.)+H_(2)O(L)`.

Discussion

2065.	What are isomers ? Give example.
Answer» Solution :COMPOUNDS with identical molucular formula but different structures are called STRUCTURAL isomers. EX : n - butane `H-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`

Discussion

2066.	Which of the following solutions would you use test the pH of a given sample?
Answer» BLUE litmus solution Red litmus solution Universal INDICATOR solution A mixture of blue and red litmus SOLUTIONS Answer :C

Discussion

2067.	Write the reactions for the conversion of ethene to dichloroethane
Answer» SOLUTION :`CH_2 = CH_2 + CL - Cl to ClCH_2 - CH_2Cl`

Discussion

2068.	Which element is bigger in size, lithium (Z = 3) or Sodium (Z = 11) and why?
Answer» Solution :Lithium (Li) atom has only TWO SHELLS K and L in it, whereas a sodium (Na) atom has THREE shells KL and M. Since a sodium atom has one more shell than a lithium atom, itis bigger in size

Discussion

2069.	Write the positions of metallic, nonmetallic and metalloid elements in the modern periodic table.
Answer» Solution :In the modern PERIODIC table, METALLIC elements are on the LEFT side while non-metallic elements are on the RIGHT side. Metalloids or SEMIMETALS are in the middle of the periodic table.

Discussion

2070.	Translate the following statements into chemical equations and then balance them. Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
Answer» SOLUTION :`3BaCl_2(AQ)+Al_2(SO_4)_2(aq)to2AlCl(aq)+3BaSO_4(s)`

Discussion

2071.	Which of the following are exothermic processes ? (i) Reaction of water with quick lime (ii) Dilution of an acid (iii) Evaporation of water (iv) Sublimation of camphor (crystals)
Answer» (i) and (ii) (ii) and (III) (i) and (iv) (iii) and (iv) SOLUTION :Heat is EVOLVED only when water reacts with quick LIME when the acid is diluted with water.

Discussion

2072.	Which of the following statements is not a correct statement about the trends when going from left to right across the periods of Periodic Table ?
Answer» The elements become less metallic in nature The number of VALENCE ELECTRONS increases. The atoms lose their electrons more easily. The oxides become more acidic. Solution :The atoms lose the electrons less easily as we MOVE from left to RIGHT in the PERIODIC Table because metallic character decreases.

Discussion

2073.	The three imaginary elements X, Y and Z represent a Dobereiner's triad. If the atomic mass of element X is 14 u and that of element Y is 46 u, then the atomic mass of element Z will be .........
Answer» 28 60 78 72 Solution :According to the law of Dobereiner.s triad, Atomic mass of Y `=("Atomic mass of X + Atomic mass of Z")/(2)` `46=("14 + Atomic mass of Z")/(2)` 92 = 14 + Atomic mass of Z `:.` Atomic mass of Z = 92 - 14 = 78 U]

Discussion

2074.	Which one of the following is an example for carbocyclic compound?
Answer» Benzene Tolquene Propane Furan Answer :D

Discussion

2075.	What isa combination reaction ? State one example giving balanced chemicalequation for the reaction .
Answer» Solution :A reaction in which two or more simple SUBSTANCES combine to form a single product. Example : `C+O_(2) overset ("BURN") rarr CO_(2)` `2H_(2)+O_(2)rarr2H_(2)O`

Discussion

2076.	What is rusting ? How does (i) the presence of impurities in the metal (ii) presence of electrolyte in water affect rusting ?
Answer» Solution :Rusting. When IRON is EXPOSED to atmospheric conditions, it reacts with AIR or water in the environment to from undesirable red BROWN coating. This process is called rusting. `underset("Iron")(4Fe)+underset("Oxygen")(3O_(2))tounderset("Ferric oxide")(2Fe_(2)O_(3))` `underset("Ferric oxide")(2Fe_(2)O_(3))+underset("(Moisture)")(xH_(2)O)tounderset("(Hydrated iron (III) oxide)")underset("Rust")(Fe_(2)O_(3)*xH_(2)O)` (i) The presence of impurities in the metal speed up the rusting process. Therefore, pure iron does not rust. (II) The presence of electrolytes in water also speeds up the process of rusting. Therefore, rusting of iron in water (containing sodium chloride) occur quicker than in distilled water.

Discussion

2077.	Which of the following statements is not a correct statement about the trends when going from left to right across the periods of Periodic Table ? (a) The elements become less metallic in nature. (b) The number of valence electrons increases. (c) The atoms lose their electrons more easily. (d) The oxides become more acidic.
Answer» Solution :Statement (c) is not correct. In FACT, the atoms lose their electrons with GREATER DIFFICULTY as we MOVE from left to right in a PERIOD. Other statements are correct.

Discussion

2078.	What are covalent compounds ? Why are they different from ionic compounds ? List their three characteristic properties.
Answer» Solution :Covalent compounds are the compounds that contain covalent bonds in the molecule. A covalent bond is formed by sharing of electrons between the atoms. While a covalent compound contains covalent bonds, the ionic compound is made up of ionic bond which is formed by transference of electrons from one atom to the other. Characteristics of covalent compounds : (i) These compounds show LOW melting points and boiling points because the INTERMOLECULAR forces are WEAK. (ii) Such compounds are poor conductors of electricity. (iii) Generally insoluble or less soluble in water but soluble in ORGANIC SOLVENTS.

Discussion

2079.	What is used for whitewashing of the walls of the house carried out ? Explain the preparation by showing chemical equation.
Answer» Solution :Solution of lime water - `Ca(OH)_(2)` is used for whitewashing the walls of the house. It is prepared by slaking of lime as shown in the following reaction: `CaO(s) +H_(2)O(I) to underset("(Lime water)")(underset("Solution of slaked lime")(Ca(OH)_(2)(AQ))` Solution of lime water is applied to the walls of the house, then it reacts slowly with the `CO_(2)` GAS of air and a thin LAYER of `CaCO_(3)` is formed on walls after two to three days. As a RESULT walls appear shining white. `underset("Calcium hydroxide")(Ca(OH)_(2)(aq))+ CO_(2)(G) to underset("Calcium carbonate")(CaCO_(3)(s))+H_(2)O(I)`

Discussion

2080.	What are alloys ?
Answer» SOLUTION :An alloy is the homogeneous mixture of two more metals or metals and non metals. For EXAMPLE brass is an alloy of COPPER and zinc.

Discussion

2081.	Write the formula of functional group (a) alcohol"" (b)aldehyde .
Answer» SOLUTION :

Discussion

2082.	The symbol (aq) is used to denote
Answer» LIQUID STATE of compound solution is PREPARED in water both of the above None Answer :B

Discussion

2083.	Which of the following statements is correct ?
Answer» In a mixture the COMPONENTS are present in a definite ratio by mass. The boiling point of water is UNCERTAIN . A COMPOUND is FORMED by the combination of TWO or more elements in a definite ratio by mass. Gun powder melts at a particular temperature. Answer :C

Discussion

2084.	What is neutralization reaction?
Answer» SOLUTION :It is another type of displacement REACTION in which the acid reacts with the base to form a salt and water.It is CALLED neutralization as both acid and base neutralizes each other. `underset(["Base"])(NaOH_((aq)))underset("+")(+)underset(["Acid"])(HCl_((aq)))underset(to)(to)underset(["Salt"])(NaCl+_((aq)))underset("+")(+)underset(["water"])(H_(2)O_((l)))`

Discussion

2085.	What is the total number of covalent bonds in a molecule of ethane?
Answer» 2 3 5 7 Answer :D

Discussion

2086.	Write the chemical formula of baking soda. How is baking soda prepared? Write the reaction which takes place when it is heated during cooking.
Answer» Solution :The CHEMICAL formula of baking SODA is `NaHCO_3` It is prepared by USING sodium chloride. `NaCl+H_2O+CO_2+NH_3 toNH_4Cl+NaHCO_3` On HEAT i n g: `2NaHCO_3 to^(Heat) Na_2CO_3+H_2O+CO_2`

Discussion

2087.	What is an oxidation reaction? Given an example of oxidation reaction. Is oxidation an exothermic or an endothermic reaction?
Answer» Solution :The reaction in which oxygen combines with other elements or compounds is known as an oxidation reaction. For EXAMPLE, burning of hydrogen is an oxidation process in which hydrogen combines with oxygen to form water. `2H_(2)(g)+O_(2)(g)rarr2H_(2)O(l)` Oxidation REACTIONS are exothermic.

Discussion

2088.	Which of the following hydrocarbon can decolourise bromine water?
Answer» `C_(4)H_(6)` `C_(4)H_(8)` `C_(3)H_(6)` all these Solution :Only UNSATURATED hydrocarbons (containing double or triple bonds) decolourises BROMINE water `C_(4)H_(6)to` ALKYNE (triple bond) `C_(4)H_(8)to` alkene (double bond) `C_(3)H_(6)to` alkene(doubled bond)

Discussion

2089.	Which one of the following represent the mass of 0.5 moles of water molecules?
Answer» 18 g 1.8 g 9 g 4.5 g Solution :`"Mole"=("MASS")/("Molecular mass")` `"Mass"="Mole"XX"Molecular mass"` `=0.5xx18=9g`.

Discussion

2090.	Write the formulae and names of the first four members of alkane family.
Answer» Solution :(i)METHANE `(CH_4)` (ii) Ethane `(C_2H_6)` (iii) PROPANE `(C_3H_8)` (iv) BUTANE `(C_4H_10)`

Discussion

2091.	Translate the following statements into chemical equations and balance them. Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
Answer» SOLUTION :`2K(s)+2H_(2)O(L)to 2KOH (aq.)+H_(2)(g)`.

Discussion

2092.	What is the smell of acetic acid ?
Answer» SOLUTION :The SMELL of acetic ACID is PUNGENT and irritating like that of VINEGAR.

Discussion

2093.	The size of the nucleus is approximately
Answer» `10^(18)` m `10^(-10)` m `10^(-8)` m none of these ANSWER :D

Discussion

2094.	Write the name and molecular formula of an organic compound having its name suffixed with '-ol' and having two carbon atoms in the molecule. With the help of a balanced equation indicate what happens when it is heated with excess of conc. H_(2)SO_(4).
Answer» SOLUTION :The organic compound is ethanol. Its molecular formula is `C_(2)H_(6)O` and structural formula is `C_(2)H_(5)OH or CH_(3)CH_(2)OH`. `underset("Ethanol")(CH_(3)CH_(2)OH) underset("HEAT")overset("Conc. "H_(2)SO_(4))to underset("Ethene")(CH_(2)=CH_(2)) +H_(2)O`

Discussion

2095.	When quick lime is added to water, a hissing sound is produced. Write the chemical reaction and state the type of reaction that takes place.
Answer» SOLUTION :`CaO+ H_(2)O to Ca(OH)_(2)+"Heat"` This type of REACTION is EXOTHERMIC and combination.

Discussion

2096.	What is covalency of Al in [AlCl_4]^(-) ?
Answer» ANSWER :4

Discussion

2097.	Which of the following property of water can be used to explain the spherical shape of rain droplets ?
Answer» viscosity surface tension pressure vaporisation Answer :B

Discussion

2098.	Which of the following reactions is possible ?
Answer» `FeSO_(4) + CU to CuSO_(4) +Fe` `CuSO_(4) +Fe to FeSO_(4) + Cu` `Cu+ZnSO_(4) to CuSO_(4) + ZN` NONE of these Answer :B

Discussion

2099.	Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate) ?
Answer» Solution :If the soil is ACIDIC in nature, the above TREATMENT is DONE to NEUTRALIZE the soil.

Discussion

2100.	Which of the following properties make(s) aluminium useful for producing household utensils ?
Answer» LOW melting POINT High THERMAL condutivity High malleability Good electrical CONDUCTIVITY Answer :B::D

Discussion

Explore topic-wise InterviewSolutions in .

What happens when bromine water is added to ethene gas?

What will be the pH of solution which turns red litmus Blue ?

while eating food, you spillsome curry on your shirt. You immediately scrub with soap, what happens to its yellow colour on scrubbing with soap ? What happens to the stain when the shirt is washed with plenty of water ?

List the points of differences between homogeneous and heterogenous mixtures.

Why are decomposition reactions called the opposite of combination reactions ? Write equations for these reactions.

Which is state function ?

When copper carbonate is heated ,the products formed are………….,…………….and change of colour from…….to ………………..is observed.

Which one of the following is an alkali metal?

To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is

Which elements have the largest and the smallest atoms?

What do you understand by the term natural selection?

Which of the compounds has an aldehyde group ?

Write the balanced chemical equation for the following chemical reactions. Sodium hydroxide solution is treated with acetic acid to form sodium acetate and water.

What are isomers ? Give example.

Which of the following solutions would you use test the pH of a given sample?

Write the reactions for the conversion of ethene to dichloroethane

Which element is bigger in size, lithium (Z = 3) or Sodium (Z = 11) and why?

Write the positions of metallic, nonmetallic and metalloid elements in the modern periodic table.

Translate the following statements into chemical equations and then balance them. Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.

Which of the following are exothermic processes ? (i) Reaction of water with quick lime (ii) Dilution of an acid (iii) Evaporation of water (iv) Sublimation of camphor (crystals)

Which of the following statements is not a correct statement about the trends when going from left to right across the periods of Periodic Table ?

The three imaginary elements X, Y and Z represent a Dobereiner's triad. If the atomic mass of element X is 14 u and that of element Y is 46 u, then the atomic mass of element Z will be .........

Which one of the following is an example for carbocyclic compound?

What isa combination reaction ? State one example giving balanced chemicalequation for the reaction .

What is rusting ? How does (i) the presence of impurities in the metal (ii) presence of electrolyte in water affect rusting ?

What are covalent compounds ? Why are they different from ionic compounds ? List their three characteristic properties.

What is used for whitewashing of the walls of the house carried out ? Explain the preparation by showing chemical equation.

What are alloys ?

Write the formula of functional group (a) alcohol"" (b)aldehyde .

The symbol (aq) is used to denote

Which of the following statements is correct ?

What is neutralization reaction?

What is the total number of covalent bonds in a molecule of ethane?

Write the chemical formula of baking soda. How is baking soda prepared? Write the reaction which takes place when it is heated during cooking.

What is an oxidation reaction? Given an example of oxidation reaction. Is oxidation an exothermic or an endothermic reaction?

Which of the following hydrocarbon can decolourise bromine water?

Which one of the following represent the mass of 0.5 moles of water molecules?

Write the formulae and names of the first four members of alkane family.

Translate the following statements into chemical equations and balance them. Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

What is the smell of acetic acid ?

The size of the nucleus is approximately

Write the name and molecular formula of an organic compound having its name suffixed with '-ol' and having two carbon atoms in the molecule. With the help of a balanced equation indicate what happens when it is heated with excess of conc. H_(2)SO_(4).

When quick lime is added to water, a hissing sound is produced. Write the chemical reaction and state the type of reaction that takes place.

What is covalency of Al in [AlCl_4]^(-) ?

Which of the following property of water can be used to explain the spherical shape of rain droplets ?

Which of the following reactions is possible ?

Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate) ?

Which of the following properties make(s) aluminium useful for producing household utensils ?