8881 + Interview Questions in Chemistry in Class 10 Page 54 InterviewSolution

2651.	The pH decreases when milk is changed to curd. Give reason.
Answer» Solution :Change of milk to CURD curdling is also called souring of milk. It is CAUSED DUE to the formation of more LACTIC acid. Thus the number of hydrogen ions (`H^(+)` ions) increases and therefore, the pH decreases.

Discussion

2652.	The period with electrons in the shell, K, Land M .
Answer» SOLUTION :PERIOD 3 .

Discussion

2653.	The period number of an element is equal to the from left to right in a period of the periodic table.
Answer» SOLUTION :ELECTRON SHELLS

Discussion

2654.	The period and group number of an element with atomic number 7 are
Answer» 2,3 2,4 2,5 2,15 Answer :D

Discussion

2655.	The percentage of oxygen in a metallic oxide of a bivalent metal is 20.1%. The molecular weight of the compound is 79.5. Write the molecular formular of the compound, considering the symbol ofthe metal as M and find out the atomic weight of the metal.
Answer» Solution :(i) calculate the number of atoms of oxygen present in the compound (ii) calculation of the number of atoms of oxygen present in one MOLECULE of themetallic oxide from the percentage of oxygen GIVEN (III) DETERMINATION OFTHE formula of the compound (iv) calculation of atomic weight of the metal (v) `63.5`

Discussion

2656.	The percentage of metal in two metal oxides, A and B is 74.2% and 59%, respectively. Show that thelaw of multiple proportions is obeyed.
Answer» Solution :`{:("Metal Oxides",,"Percentage of Metal",,"Percentage of OXYGEN"),("A",,"74.2",,"25.8"),("B",,"59",,"41"):}` In A, 74.2g ofmetal combines with 25.8g OFOXYGEN ? combines with 1 g of oxygen ` = (74.2g)/(25.8 g) = 2.87` g In B, 59g of metal combines with 41g ofoxygen ? combines with 1 g of oxygen ` =59/41 g = 1.43` g `:.` The ratio by WEIGHT of metal combining with fixedmass of oxygen in A andB ` = 2.87 : 1.43 = 2 : 1` Hence, law of multiple proportions is OBEYED.

Discussion

2657.	The percentage of hydrogen in H_2Ois
Answer» 44.45 5.55 88.89 11.11 Solution :11.11

Discussion

2658.	The percentage of hydrogen in H_(2)O is ……………… .
Answer» 8.88 11.2 20.6 `80.0` Solution :Hint : 1 MOLE of `H_(2)O` has 2.016 g of `H_(2)` `THEREFORE"Percentage of "H_(2)=(2.016)/(18)xx100` `=11.2`

Discussion

2659.	The percentage mass of magnesium in chlorophyll is 2.68% The number of magnesium atoms in 2 g of chlorophyll is _____________
Answer» ANSWER :`1.34xx10^(21)`

Discussion

2660.	The percentage composition of elements is useful to determine ………………….and ………………….. .
Answer» SOLUTION :EMPIRICAL FORMULA, MOLECULAR formula

Discussion

2661.	The percentage by weight of O_(2) in CaSO_(4)(O=16, Ca=40, S=32) is ……………. .
Answer» `64%` `28.2%` `47.05%` `16.2%` Solution :HINT : `"% by weight of "O_(2)` `=(64)/(136)xx100=47.05%`

Discussion

2662.	The particles present in strong electrolytes are
Answer» only molecules MAINLY ions ions AD molecules only atoms Answer :B

Discussion

2663.	The particle used by Rutherford in alpha-ray scattering experiment was
Answer» neutron electron HELIUM nucleus X RAYS ANSWER :C

Discussion

2664.	The pair of elements which shows catenation is
Answer» silicon and sodium CARBON and SULPHUR carbon and CHLORINE silicon and sodium Answer :B

Discussion

2665.	The Packing efficiency in unit cell is
Answer» In sc `48%` In ccp `74%` In BCC `32%` All of the above Answer :B

Discussion

2666.	Give reason - The oxidising power of elements increases from left to right along a period.
Answer» SOLUTION :Because IONISATION ENERGY INCREASES.

Discussion

2667.	The oxides of the elements of groups 1 and 2 are _____ in nature.
Answer» ANSWER :BASIC

Discussion

2668.	The oxides of very reactive metals are reduced to metals by :
Answer» ELECTROLYTIC REDUCTION heating with carbon heating with aluminium liquation Solution :electrolytic reduction

Discussion

2669.	The oxides of highly reactive metals cannot be reduced by carbon. (TRUE/ FALSE)
Answer» ANSWER :T

Discussion

2670.	The oxidation state of 'S' in Kal(SO_(4))_(2) .12H_(2)O is
Answer» `-2` `-1` 2 `+6` ANSWER :D

Discussion

2671.	The oxidation state of Fe in Fe_(3)O_(4) is :
Answer» `+2` `+3` `(8)/(3)` `+2,+3` ANSWER :D

Discussion

2672.	The oxidation reaction which produces heat and light is
Answer» Endothermic Photochemical Combustion Exothermic Answer :C

Discussion

2673.	The oxidation of ethanol gives ethanal.
Answer» ANSWER :T

Discussion

2674.	The overuse of resources is one major cause of their ____
Answer» SOLUTION :DEPLETION

Discussion

2675.	The organic compounds that are composed of only carbon and hydrogen atoms are called………………..
Answer» SOLUTION :HYDROCARBONS

Discussion

2676.	The organic compounds are usually poor conductors of elelctricity .
Answer» ANSWER :T

Discussion

2677.	The organic compound used in cough syrups and in digestive syrups is……………….
Answer» ETHANOIC acid Ethyl ethanoate METHANOL ethanol Answer :D

Discussion

2678.	The organic compound used for coagulating rubber from latex is…………………..
Answer» methanoic ACID ETHANOIC acid ethanol METHANOL ANSWER :B

Discussion

2679.	The organic compound that depresses the central nervous system after consumption is……………………
Answer» ETHANOL METHANOL ACETIC acid ethyl ethanoate ANSWER :B

Discussion

2680.	The organic compound contains 2 carbon atoms, the root word according IUPAC is ____________
Answer» Meth- Eth- Prop- But- Answer :B

Discussion

2681.	The organic compound mixed with ethanol to make it spurious is:
Answer» METHANAL Methanoic acid METHANOL Ethanoic acid Solution :Methanol

Discussion

2682.	The organ which perform different function but have the same basic structure are called.
Answer» Vestigal organ Analogous organs Homologous organs Analytic organs Answer :3

Discussion

2683.	The ore which can be purified by gravity separation method is ……………….. .
Answer» HAEMATITE OXIDE ORES SULPHIDE ores both (a) and (b) ANSWER :D

Discussion

2684.	The ore of a metal is lighter than the impurities. Which method is suitable for its concentration?
Answer» ANSWER :FORTH FLOATATION PROCESS

Discussion

2685.	The Siderite is the most important ore of
Answer» ALUMINIUM iron copper `S_(8)` ANSWER :B

Discussion

2686.	The order of rectivity of Zn, Fe, Cu and Al is
Answer» Zn GT CU gt Al gt Fe Zn gt Al gt Cu gt Fe Al gt Zn gt Fe gt Cu Zngt Al gt Fe gt Cu ANSWER :C

Discussion

2687.	The order of procsses involved in the dressing of an ore is (i) grinding and crushing (ii) hand-picking (iii) Pulverisation
Answer» (i), (ii), (III) (i), (iii), (ii) (ii), (iii), (i) (ii), (i), (iii) Solution :DRESSING of ORE can be carried out by hand-picking, CRUSHING and grinding, PULVERISATION.

Discussion

2688.	The order of ease of oxidation of the ions F^(-), OH^(-), Br^(-), SO_(4)^(2-) is _______
Answer» `SO_(4)^(2-) gt F^(-) Br^(-) gt OH^(-)` `SO_(4)^(2-) lt Br^(-) lt OH^(-) lt F^(-)` `SO_(4)^(2-) gt F^(-) gt Br^(-) gt OH^(-)` `OH^(-) lt Br^(-) lt F^(-) lt SO_(4)^(2-)` SOLUTION :`SO_(4)^(2-) lt F^(-) lt Br^(-) lt OH^(-)` In an ELECTRONEGATIVE SERIES, EASE of oxidation increases from top to BOTTOM

Discussion

2689.	The orbitals p and d can form pi bonds, but the s-orbital cannot form a pi bond. Give reasons.
Answer» <P> Solution :(i) shape of orbitals (II)SHAPES of p- and d-orbitals in contrast to the shape of 's-' orbitals (III) type of overlapping in `PI` bond

Discussion

2690.	The oil drop experiment by R. A. Mullikan was performed to find
Answer» charge on the neutron charge on the ELECTRON charge on the Proton NONE of these Answer :B

Discussion

2691.	The [OH^(-)] ion concentration of a solution is 1.0xx10^(-8)M.What is the pH of the solution?
Answer» SOLUTION :The CONCENTRATION of hydroxide ion=`[OH^(-)]=1.0xx10^(-8)`m pOH=`-log_(10)[OH^(-)]` pOH=`-log_(10)(1.0xx10^(-8))` pOH=8 pH+pOH=14 `THEREFORE` pH=14-8`implies` pH=6

Discussion

2692.	The OH^- concentration of a solution is 1.0 xx 10^(-10) M. The solution is
Answer» acidic basic neutral amphoteric ANSWER :C

Discussion

2693.	The ………….. Of the elements is a period decreases from left to right and the atomic radii of the element present in a group …………..downwards .
Answer» SOLUTION : ATOMIC SIZE , INCREASES

Discussion

2694.	The odour of ethanoic acid resembles with:
Answer» TOMATO juice Kerosene orange juice vinegar ANSWER :D

Discussion

2695.	The octane number has zero value for
Answer» ISO-OCTANE n-octane n-heptane Tetra ethyl lead Solution :Octane number is USEDTO check the QUALITY of fuel. It is defined as the percentage by volume of isooctane in a mixture of isooctane and n-heptane. n-heptane has been given an octane number of zero while iso octane, the octane number of 100.

Discussion

2696.	The numerical value of ionisation energy of a unipositive ion is approximately equal to
Answer» (a) IP value of neutral ATOM (b) EA value of neutral atom (c) IP value of dipositive ion (d) EA velue of dipositive ion Solution :The numerical value of ionisation energy of a uinpositive ion is APPROXIMATELY EQUAL to the electron AFFINITY of dipositive ion.

Discussion

2697.	The number of which of the following atomic particles plays a major role in classification of elements in the Modern Periodic Table?
Answer» NEUTRON ELECTRON PROTON all of the these ANSWER :C

Discussion

2698.	The number of water molecules present in a molecule of copper sulphate crystal is
Answer» 2 4 7 5 Answer :D

Discussion

2699.	The number of valence electrons present in Ca atom
Answer» 3 2 8 6 Answer :B

Discussion

2700.	The number of valence electrons present in the 12th element of any period is
Answer» 12 2 6 0 Answer :B

Discussion

Explore topic-wise InterviewSolutions in .

The pH decreases when milk is changed to curd. Give reason.

The period with electrons in the shell, K, Land M .

The period number of an element is equal to the from left to right in a period of the periodic table.

The period and group number of an element with atomic number 7 are

The percentage of oxygen in a metallic oxide of a bivalent metal is 20.1%. The molecular weight of the compound is 79.5. Write the molecular formular of the compound, considering the symbol ofthe metal as M and find out the atomic weight of the metal.

The percentage of metal in two metal oxides, A and B is 74.2% and 59%, respectively. Show that thelaw of multiple proportions is obeyed.

The percentage of hydrogen in H_2Ois

The percentage of hydrogen in H_(2)O is ……………… .

The percentage mass of magnesium in chlorophyll is 2.68% The number of magnesium atoms in 2 g of chlorophyll is _____________

The percentage composition of elements is useful to determine ………………….and ………………….. .

The percentage by weight of O_(2) in CaSO_(4)(O=16, Ca=40, S=32) is ……………. .

The particles present in strong electrolytes are

The particle used by Rutherford in alpha-ray scat­tering experiment was

The pair of elements which shows catenation is

The Packing efficiency in unit cell is

Give reason - The oxidising power of elements increases from left to right along a period.

The oxides of the elements of groups 1 and 2 are _____ in nature.

The oxides of very reactive metals are reduced to metals by :

The oxides of highly reactive metals cannot be reduced by carbon. (TRUE/ FALSE)

The oxidation state of 'S' in Kal(SO_(4))_(2) .12H_(2)O is

The oxidation state of Fe in Fe_(3)O_(4) is :

The oxidation reaction which produces heat and light is

The oxidation of ethanol gives ethanal.

The overuse of resources is one major cause of their ____

The organic compounds that are composed of only carbon and hydrogen atoms are called………………..

The organic compounds are usually poor conductors of elelctricity .

The organic compound used in cough syrups and in digestive syrups is……………….

The organic compound used for coagulating rubber from latex is…………………..

The organic compound that depresses the central nervous system after consumption is……………………

The organic compound contains 2 carbon atoms, the root word according IUPAC is ____________

The organic compound mixed with ethanol to make it spurious is:

The organ which perform different function but have the same basic structure are called.

The ore which can be purified by gravity separation method is ……………….. .

The ore of a metal is lighter than the impurities. Which method is suitable for its concentration?

The Siderite is the most important ore of

The order of rectivity of Zn, Fe, Cu and Al is

The order of procsses involved in the dressing of an ore is (i) grinding and crushing (ii) hand-picking (iii) Pulverisation

The order of ease of oxidation of the ions F^(-), OH^(-), Br^(-), SO_(4)^(2-) is _______

The orbitals p and d can form pi bonds, but the s-orbital cannot form a pi bond. Give reasons.

The oil drop experiment by R. A. Mullikan was performed to find

The [OH^(-)] ion concentration of a solution is 1.0xx10^(-8)M.What is the pH of the solution?

The OH^- concentration of a solution is 1.0 xx 10^(-10) M. The solution is

The ………….. Of the elements is a period decreases from left to right and the atomic radii of the element present in a group …………..downwards .

The odour of ethanoic acid resembles with:

The octane number has zero value for

The numerical value of ionisation energy of a unipositive ion is approximately equal to

The number of which of the following atomic particles plays a major role in classification of elements in the Modern Periodic Table?

The number of water molecules present in a molecule of copper sulphate crystal is

The number of valence electrons present in Ca atom

The number of valence electrons present in the 12th element of any period is

The particle used by Rutherford in alpha-ray scattering experiment was