Recent questions tagged 89

The work done to raise a mass m from the surface of the earth to a height h, which is equal to the radius of the earth, is

asked Jul 8, 2019 by pady_1

1 answer

The homologue of ethyne is :

asked Dec 19, 2018 by pady_1

0 answers

A mixture contains $16\;g$ of oxygen, $28\; g$ of nitrogen and $8\; g$ of $CH_4$. Total pressure of mixture is $740\;mm$. What is the partial pressure of nitrogen in $mm$?

asked Dec 19, 2018 by pady_1

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The electronic configuration of group III elements is :

asked Dec 19, 2018 by pady_1

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What is the volume (in litres) of oxygen at STP required for complete combustion of 32 g of $CH_4$ ? (Molecular weight of $CH_4$ is 16)

asked Dec 11, 2018 by pady_1

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Following reaction $(CH_3)_3 CBr + H_2O \to (CH_3)_3 COH + HBr$ is an example of :

asked Dec 11, 2018 by pady_1

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An ether is more volatile than an alcohol having the same molecular formula. This is due to :

asked Dec 11, 2018 by pady_1

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For 1 molal aqueous solution of the following compounds, which one will show the highest freezing point ?

asked Dec 11, 2018 by pady_1

1 answer

A water sample has ppm level concentration of following anions $F^- = 10, \; SO_4^{2-} = 100; \; NO_3^- = 50$ The anion/anions that make/makes the water sample unsuitable for drinking is/are :

asked Dec 11, 2018 by pady_1

0 answers

A man is walking towards a vertical pillar in a straight path, at a uniform speed. At a certain point A on the path, he observes that the angle of elevation of the top of the pillar is $30^{\circ}$. After walking for 10 minutes from A in the same direction, at a point B, he observes that the angle of elevation of the top of the pillar is $60^{\circ}$. Then the time taken (in minutes) by him, from B to reach the pillar, is :

asked Dec 11, 2018 by pady_1

1 answer

If $f(x)=2 \tan^{-1}x+\sin^{-1} (\frac{2x}{1+x^2}),\; x>1$, then $f(5)$ is equal to:

asked Dec 11, 2018 by pady_1

1 answer

For complete combustion of ethanol, $C_2H_5OH (\ell) + 3O_2 (g) \to 2CO_2 (g) + 3H_2O (\ell)$, the amount of heat produced as measured in bomb calorimeter, is $1364.47\; kJ \;mol^{–1}$ at $25^{\circ}C$. Assuming ideality the Enthalpy of combustion, $\Delta_CH$, for the reaction will be: $(R = 8.314\; kJ \;mol^{–1} )$

asked Dec 11, 2018 by pady_1

0 answers

The magnetic field in a travelling electromagnetic wave has a peak value of 20 nT. The peak value of electric field strength is :

asked Dec 11, 2018 by pady_1

0 answers

In which of the following pairs the two species are not isostructural ?

asked Dec 11, 2018 by pady_1

0 answers

The entropy change involved in the isothermal reversible expansion of 2 moles of an ideal gas from a volume of $10 \; dm^3$ to a volume of $100\; dm^3$ at $27^ {\circ} C$ is :

asked Dec 11, 2018 by pady_1

0 answers

For two data sets, each of size 5, the variances are given to be 4 and 5 and the corresponding means are given to be 2 and 4, respectively. The variance of the combined data set is

asked Dec 11, 2018 by pady_1

0 answers

Statement -1 : $\sim (p \leftrightarrow \sim q) $ is equivalent to $p \leftrightarrow q$ Statement -2: $\sim (p \leftrightarrow \sim q) $ is a tautology.

asked Nov 29, 2018 by pady_1

0 answers

Consider a block of conducting material of resistivity â€˜pâ€™ shown in the figure. Current â€˜Iâ€™ enters at â€˜Aâ€™ and leaves from â€˜Dâ€™. We apply superposition principle to find voltage â€˜$\triangle$Vâ€™ developed between â€˜Bâ€™ and â€˜Câ€™. The calculation is done in the following steps: (i) Take current â€˜Iâ€™ entering from â€˜Aâ€™ and assume it to spread over a hemispherical surface in the block (ii) Calculate field E(r) at distance â€˜râ€™ from A by using Ohmâ€™s law E = pj, where j is the current per unit area at â€˜r (iii) From the â€˜râ€™ dependence of E(r), obtain the potential V(r) at r. (iv) Repeat (i), (ii) and (iii) for current â€˜Iâ€™ leaving â€˜Dâ€™ and superpose results for â€˜Aâ€™ and â€˜Dâ€™. QUESTION : $\triangle$V measured between B and C is

asked Nov 29, 2018 by pady_1

0 answers

Which of the following reactions will yield, 2, 2-dibromopropane ?

asked Nov 29, 2018 by pady_1

0 answers

In Langmuir's model of adsorption of a gas on a solid surface :

asked Nov 13, 2018 by pady_1

0 answers

Aluminium oxide may be electrolysed at $1000^{\circ} C$ to furnish aluminium metal (Atomic mass =27 amu; 1 faraday= 96,500 Coulombs). The cathode reaction is $Al^{3+} + 3e^- \to Al^0$ To prepare 5.12 Kg of aluminium metal by this method would require :

asked Nov 5, 2018 by pady_1

0 answers

The maximum number of $90^{\circ}$ angles between bond pair of electrons is observed in

asked Nov 5, 2018 by pady_1

1 answer

Which of the following compounds can form a zwitterion ?

asked Aug 21, 2018 by pady_1

1 answer

The function of copper ions in copper releasing IUD's is :

asked Aug 21, 2018 by pady_1

1 answer

A system of rotating crops with legume or grass pasture to improve soil structure and fertility is called -

asked Aug 21, 2018 by pady_1

1 answer

Select the wrong statement -

asked Aug 21, 2018 by pady_1

1 answer

Identity Z in the sequence of reactions : $CH_3 CH_2 CH = CH_2 \xrightarrow{HBr/H_2O_2} Y \xrightarrow{C_2H_5ONa} Z$

asked Aug 20, 2018 by pady_1

1 answer

The order of stability of the following tautomeric compounds is

asked Aug 20, 2018 by pady_1

1 answer

Which nomenclature is not according to IUPAC system ?

asked Aug 20, 2018 by pady_1

1 answer

In a set of reactions m - bromobenzoic acid gave a product D. Identify the product D.

asked Aug 16, 2018 by pady_1

0 answers

Which of the following represents the correct order of increasing electron gain enthalpy with negative sign for the elements O, S, F and Cl?

asked Jul 26, 2018 by pady_1

1 answer

Benzene reacts with $CH_3 Cl $in the presence of anhydrous $AlCl_3$ to form -

asked Jul 26, 2018 by pady_1

1 answer

With which one of the following elements silicon should be doped so as to give p-type of semiconductor?

asked Jul 26, 2018 by pady_1

2 answers

Which one of the following on treatment with 50% aqueous sodium hydroxide yields the corresponding alcohol and acid :

asked Jul 26, 2018 by pady_1

1 answer

In which of the following molecules all the bonds are not equal:-

asked Jul 25, 2018 by pady_1

1 answer

In a set of reactions acetic acid yielded a product D

asked Jul 24, 2018 by pady_1

0 answers

The standard e.m.f. of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V a 25ºC. The equilibrium constant of the reaction would be :- (Given $F = 96500 \;C \;mol^{–1}$; $R = 8.314 JK^{–1} mol^{–1}$)

asked Jul 24, 2018 by pady_1

1 answer

The radioisotope, tritium ($ ^3_1H$) has a half-life of 12.3 years. If the initial amount of tritium is 32 mg, how many milligrams of its would remain after 49.2 years :

asked Jul 24, 2018 by pady_1

1 answer

are

asked Jul 23, 2018 by pady_1

1 answer

In X- H ----- Y, X and Y both are electronegative elements :

asked Jul 20, 2018 by pady_1

1 answer

For the disproportionation of copper :$2Cu^+\rightarrow Cu^{+2}+Cu$, Eº is : - (Given Eº for $\frac{Cu^{+2}}{Cu}$ is 0.34 V & Eº for $\frac{Cu^{+2}}{Cu^+ }$is 0.15 V :

asked Jul 20, 2018 by pady_1

1 answer

$4NH_3+5O_2\rightarrow6H_2O+4NO$ When one mole ammonia and one mole oxygen taken :

asked Jun 15, 2018 by pady_1

1 answer

The number of days left in the month of November are half of the number of days already passed. How many days are left in the month ?

asked Dec 31, 2015 by pady_1

1 answer

The table shows the average temperatures for London, England, for each month of the year. What is the median of these values?

asked Dec 31, 2015 by pady_1

1 answer

Find the area of a rectangle whose length is 21 m and breadth is 500 cm.

asked Dec 31, 2015 by pady_1

1 answer

Find the following: $\large\frac{9}{14}$ of $7 \large\frac{7}{17}$

asked Dec 31, 2015 by pady_1

0 answers

Dean earns Rs 722 per hour. Last week, he worked 9 hours on Monday, 6 hours on Tuesday, and 9 hours on Wednesday. He had Thursday off, and then he worked 10 hours on Friday. How much money did Dean earn in all last week?

asked Dec 31, 2015 by pady_1

1 answer

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