List of top Chemistry Questions

A system has internal energy equal to $E_1$, 450 J of heat is taken out of it and 600 J of work is done on it. The final energy of the system will be
$A$ system absorbs $50 \,kj$ heat and does $20\, kj$ of work. What is the net change in the internal energy of the system?
A suspension of $Ca(OH)_2$ in water is called
A standard hydrogen electrode has a zero potential because
A solution of a compound $X$ in dilute $HCl$ on treatment with a solution of $BaCl_2$ gives a white precipitate of a compound $Y$ which is insoluble in cone. $HNO_3$ and conc. $HCl$. Compound $X$ imparts golden yellow colour to the flame. $\underset{\text{(imparts golden yellow colour)}}{ {X (Solution \,in \,dilute HCl) }}$ $+\, {BaCl2 -> }$$\underset{\text{Whit ppt}}{ {Y}}$ $ {->[\text{Conc}. HNO_3][\text{Conc}.HCl] Insoluble}$ What are compounds $X$ and $Y$ ?
A solution of 10 ml $\frac{M}{10} {FeSO_4}$ was titrated with $ {KMnO_4}$ solution in acidic medium. The amount of $ {KMnO_4}$ used will be :
A solid $X^{+} Y^{-}$ has a bee structure. If the distance of closest approach between the two atoms is 173 pm, the edge length of the cell is
A solution containing 0.319 g of $CrCl_3?6H_2O$ was passed through a certain exchange resin and acid coming of cation exchange resin required 28.5 mL of 0.125 M NaOH. The correct formula of complex is (mol. wt. of complex = 266.7)
A solid is made of two elements $X$ and $Z$. The atoms $Z$ are in $ccp$ arrangement while atoms $X$ occupy all the tetrahedral sites. What is the formula of the compound ?
A sample of $O_2$ gas is collected over water at $23 ^{\circ}C$ at a barometric pressure of $751\, mm\, Hg$ (vapour pressure of water at $23^{\circ}C$ is $21\, mm\, Hg$).The partial pressure of $O_2$ gas in the sample collected is
A real gas obeying van der Waal equation will resemble ideal gas if the
A primary alcohol, $C_3H_8O(A)$ on heating with sulphuric acid undergo dehydration to give an alkene, $B$. $B$ when reacted with $HCl$ gave $C$, which on treatment with aqueous $KOH$ gives compound $D(C_3H_8O)$. $A$ and $D$ are
A primary alkyl halide would prefer to undergo
A positive catalyst only
A person living in Shimla observed that cooking food without using pressure cooker takes more time. The reason for this observation is that at high altitude
A pair of compounds and a test name is given in each option. Find the option where the test given cannot be used to differentiate the pair of compounds.
In the following reaction: $CH_3ONa + CO {->[\Delta][{\text{Under pressure}}, HCl]} A$ Here $'A'$ is
A narrow spectrum antibiotic is active against____.
A naturally occurring substance from which a metal can be profitably extracted is known, as
A mole of $N_2H_4$ loses $10$ mol of electrons to form a new compound $Y$. Assuming that all the nitrogen appears in the new compound, what is the oxidation state of nitrogen in $Y$? (There is no change in the oxidation number of hydrogen.)
A mole of $ {N_2H_4}$ loses ten moles of electrons to form a new compound Y. Assuming that all the nitrogen appears in the new compound, what is the oxidation state'of nitrogen in Y? (there is no change in the oxidation number of hydrogen)
A mixture of three gases, ethane, ethene and ethyne are passed through ammoniacal solution of cuprous chloride. The emergent gas(es) after it was passed through solution contained
A mixture of $C_3H_8$ and $CH_4$ exerts a pressure of 320 mm Hg at temperature T K in a V litre flask. On complete combustion, gaseous mixture contains $CO_2$ only and exerts a pressure of 448 mm Hg under identical conditions. Hence mole fraction of $C_3H_8$ in the mixture is
A mixture of dihydrogen and dioxygen at one bar pressure contains 20% by weight of dihydrogen. What would be the partial pressure of dihydrogen in bar?
A metallic element exists as cubic lattice. Each edge of the unit cell is $2.88 \, \mathring A$. The density of the metal is 7.20 g $cm^{-3}$. How many unit cell will be present in 100 g of the metal?