List of top Chemistry Questions on Some basic concepts of chemistry asked in NEET (UG)

A compound X contains 32% of A, 20% of B and remaining percentage of C. Then, the empirical formula of X is:
(Given atomic masses of A=64; B=40; C=32 u)

Which one of the followings has maximum number of atoms ?

In which case is the number of molecules of water maximum ?

A mixture of $2.3 \,g$ formic acid and $4.5 \,g$ oxalic acid is treated with cone. $H_2SO_4$. The evolved gaseous mixture is passed through $KOH$ pellets. Weight (in $g$ ) of the remaining product at $STP$ will be

What is the mass of the precipitate formed when 50 mL of 16.9% solution of $AgNO_3$ is mixed with 50 mL of 5.8% $NaCl$ solution ? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl =35.5)

The number of water molecules is maximum in :

If avogadro number $N_A$, is changed from ${6.022 \times 10^{23} \, mol^{-1} }$ to ${6.022 \times 10^{20} \, mol^{-1} }$ , this would change :

A mixture of gases contains $H_2$ and $O_2$ gases in the ratio of 1 : 4 (w/w). What is the molar ratio of the two gases in the mixture?

1.0 g of magnesium is burnt with 0.56 g O₂ in a closed vessel. Which reactant is left in excess and how much? (At. wt. Mg = 24 ; O = 16)

In the Kjeldahl's method for estimation of nitrogen present in a soil sample, ammonia evolved from 0.75 gm of sample neutralized 10 mL of 1 M H₂SO₄, The percentage of nitrogen in the soil is:

When 22.4 L of $H_{2(g)}$ is mixed with 11.2 L of $Cl_{2(g)}$, each at STP, the moles of $HCl_{(g)}$ formed is equal to

$6.02 \times 10^{20}$ molecules of urea are present in 100 mL of its solution. The concentration of solution is :-

$25.3 \, g$ of sodium carbonate, $Na_2CO_3$ is dissolved in enough water to make $250 \, mL$ of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion, $Na^+$ and carbonate ions,$CO^{2-}_3$ are respectively (Molar mass of $Na_2CO_3 = 106 \, g \, mol^{-1}$)

What volume of oxygen gas $(O_2)$ measured at $0^\circ C$ and 1 atm, is needed to bum completely 1L of propane gas $(C_3H_8)$ measured under the same conditions?

How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl?

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be

An element, $X$ has the following isotopic composition; ${ }^{200} X : 90 \%$ ${ }^{199} X : 8.0 \%$ ${ }^{202} X : 2.0 \%$ The weighted average atomic mass of the naturally-occurring element $X$ is closest to:

The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270kg of aluminum metal from bauxite by the Hall process is: (Atomic mass Al = 27)

Which has maximum number of molecules :-

Percentage of Se in peroxidase anhydrous enzyme is 0.5% by weight (at. wt = 78.4) then minimum molecular weight of peroxidase anhydrous enzymes is

Which one correctly matched

Sp. vol. of cylinderical virus particle is 6.02 × 10^-2 cc/gm. Whose radius and length are 7 Å & 10Å respectively. If NA = 6.02 × 10^23. Find mol. wt. of virus

Which pair have not equal dimensions:

A compound contains atoms of three elements $A, B$ and $C$. If the oxidation number of $A$ is $+ 2, B$ is $+5$ and that of $C$ is $- 2$, the possible formula of the compound is