Which of the following molecules specie has the minimum number of lone pairs ? 

A quantity of $2.0\ g$ of a triatomic gaseous element was found to occupy a volume of $448\ ml$ at $76\ cm$ of $Hg$ and $273\ K$.

Which of the following gas molecule has the longest mean free path at the same pressure and temperature?

Two gases X and Y have their molecular speed in ratio of $3:1$ at certain temperature. The ratio of their molecular masses $M _x:M _y$ is?

The waste of nuclear power plant contains $C^{12}$ and $C^{14}$ in ratio of $4:1$ by moles. What is the molecular mass of methane gas produced from this disposed of $C^{12}$ and $C^{14}$ are $98\%$ and $2\%$, respectively. 

A gaseous mixture of three gases A, B and C has a pressure of $10$ atm. The total number of moles of all the gases is $10$. If the partial pressures of A and B are $3.0$ and $1.0$ atm, respectively, and if C has molecular mass of $2.0$, what is the mass of C, in g, present in the mixture?

Which of the following will have the composition (by mass) mass similar as that of acetic acid?

A quantity of $5.0$g of a mixture of He and another gas occupies a volume of $1.5$l at $300$K and $750$mm Hg. The gas freezes at $270$K. At $15$K, the pressure of the gas mixture is $8$mm Hg(at the same volume). What is the molecular mass of the gas?

A protein, isolated from a bovine preparation, was subjected to amino acid analysis. The amino acid present in the smallest amount was lysine, $C _6H _{14}N _2O _2$ and the amount of lysine was found to be $365\ mg$ per $100\ g$ protein. What is the minimum molecular mass of the protein?   

A mixture contains $NaCl$ and unknown chloride $MCl$. When $1\ g$ of this mixture is dissolved in water and excess of $AgNO _{3}$ Solution is added to it, $2.567\ g$ of white precipitate is obtained. In another experiment, $1\ g$ of the same original mixture is heated to $300^{o}C$. Some vapour come out which are absorbed in acidified $AgNO _{3}$ solution by which $1.341\ g$ of white precipitate is formed. The molecular mass of unknown chloride is

If the yield of chloroform obtainable from acetone and bleaching powder is $75\%$, what mass of acetone is require for producing $30\ g$ of chloroform? 

1 mole of a compound contains 1 mole of C and 2 moles of O. The molecular weight of the compound is:

What is the weight of $3$ gram atoms of sulphur?

Iron pyrites has formula $FeS _2. (Fe = 56; S = 32)$. What is the mass of sulfur contained in 30 grams of pyrites?

The mass of one molecule of water is approximately:

In an experiment, the following four gases were produced. 11.2 L of which two gases at STP will weigh 14 g ?

If of conservation of mass was to hold true, then 20.8 g of ${ BaCl } _{ 2 }$ on reaction with 9.8 g of ${ H } _{ 2 }{ SO } _{ 4 }$ will produce 7.3 g of $HCl$ and ${ BaSO } _{ 4 }$ equal to :

The number of electrons which will together weigh one gram is :

What is the mass of oxalic acid, $ H _{2}C _{2}O _{4},$ which can be oxidized to $ CO _{2}$ by 100 ml of $MnO _{4}^{-}$ solution, 10 ml of which is capable of oxidizing 50 ml of $ 1.00 N\ I^{-} $ to $ I _{2}?$

A definite mass of $ H _{2}O _{2} $ is oxidized by excess of acidified $ KMnO _{4} $ and acidified $ K _{2}Cr _{2}O _{7} $, in separate experiments. Which of the following is/are correct statements? 
(K = 39, Cr = 52, Mn = 55 )

Two acids $ H _{2}SO _{4} $ and $ H _{3}PO _{4} $ are neutralized separately by the same amount of an alkali when sulphate and dihydrogen orthophosphate are formed, respectively. Find the ratio of the masses of $ H _{2}SO _{4} $ and $ H _{3}PO _{4} $ 

A gaseous alkane is exploded with oxygen. The volume of ${O} _{2}$ for complete combustion of alkane to $C{O} _{2}$ formed is in the ratio $7:4$. The molecular formula of alkane is:

A gaseous oxide contains 30.4% of nitrogen, one molecule of which contains one nitrogen atom. The density of the oxide relative to oxygen is: