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NEET Some Basic Concepts of Chemistry PYQs with Solutions

370 previous year questions from Some Basic Concepts of Chemistry (NEET UG Chemistry) with answers and solutions. Numbered list, year tags, and one-tap solutions — built for serious JEE / NEET practice.

370 questionsChemistry2001–2026Answers + solutions

About Some Basic Concepts of Chemistry PYQs

Some Basic Concepts of Chemistry has 370 previous year questions in the Quantrex Academy NEET UG Chemistry bank. The 220 questions in this list come from NEET (168), AIIMS (24), JIPMER (16) and 1 other source, spanning 2001 to 2026. Each question opens on its own page with the options, the correct answer and the worked solution where available.

NEET Some Basic Concepts of Chemistry PYQs with Solutions

About Some Basic Concepts of Chemistry PYQs

Questions by year (this list)

Some Basic Concepts of Chemistry questions with solutions

Calculate the mass of potassium chlorate required to liberate 6.72 dm^3 of oxygen at STP. [Molar mass of potassium chlorate = 122.5 g mol^ -1 ]

Find the mass of lime obtained by heating 500 g of 90\% pure lime stone. [Molar masses Ca=40 g/mol, O=16 g/mol \ and C=12 g/mol]

A coordination complex contains 2.6\ \% of Mg. Find the number of Mg atoms in 5.0 g of this sample. (gram atomic mass of Mg = 24 g )

Calculate the number of moles and molecules of chlorine in 4.48\ dm^3 of chlorine at STP.

What is the gram atomic mass of an element whose mass of one atom is 3.9853 × 10^ -23 \ g ?

Calculate the total mass and number of molecules present in 3 moles of benzene.

Which of the following gases has high vapour density at same temperature and pressure?

What is the number of moles of Cl atoms present in n moles of tear gas and in n moles of mustard gas respectively?

Calculate the number of atoms in 52 moles of argon.

Find the mass of 1 molecule of H_2SO_4 in grams.

Which of the following compounds has maximum number of molecules ?

Calculate the number of carbon atoms present in 11 g of carbon dioxide.

The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, are

When 1 dm ^3 of CO_2 gas is passed over hot coke, the volume of gaseous mixture after complete reaction at STP becomes 1.4 dm ^3 . The composition of the gaseous mixture at STP is

The number of hydrogen atoms present in 5.4 g of urea is : (Given : Molar mass of urea : 60 g mol ^ -1 , N_A : 6.022 × 10^ 23 particles mol ^ -1 )

The amount of carbon dioxide evolved upon complete combustion of 116 g of n -butane is (Given: atomic mass in amu H =1 , C =12 and O =16 )

Among the following choose the ones with equal number of atoms. A. 212 g of Na_2 CO_3(~s) [molar mass =106 ~g ] B. 248 g of Na_2 O (s) [molar mass =62 ~g ] C. 240 g of NaOH(s)

Dalton's Atomic theory could not explain which of the following?

1.0 g of H_2 has same number of molecules as in:

1 gram of sodium hydroxide was treated with 25 mL of 0.75 M HCl solution, the mass of sodium hydroxide left unreacted is equal to

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 )

The highest number of helium atoms is in

The density of 1 M solution of a compound ' X ' is 1.25 ~g ~mL^ -1 . The correct option for the molality of solution is (Molar mass of compound X=85 ~g )

The right option for the mass of CO _ 2 produced by heating 20g of 20 % pure limestone is (Atomic mass of Ca = 40 ) [ CaCO _ 3 1200K → CaO + CO _ 2 ]

The density of the solution is 2.15 ~g ~mL^ -1 , then mass of 2.5 ~mL solution in correct significant figures is

What mass of 95 % pure CaCO _ 3 will be required to neutralise 50mL of 0 . 5MHCl solution according to the following reaction? CaCO _ 3(s) + 2 HCl _ (aq) → CaCl _ 2(aq) + CO _

An organic compound contains 80 % (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of C is 12 and

Which one of the followings has maximum number of atoms?

One mole of carbon atom weighs 12g , the number of atoms in it is equal to, (Mass of carbon - 12 is 1 . 9926 × 10 ^ - 23 g)

Find empirical formula of the compound containing a metal, M=68 \% (atomic mass =34) and remaining 32 \% oxygen.

In a chemical reaction, A+B A B , if B is acting as a limiting reagent, then choose the correct option.

Calculate molarity of 63 \% w / w HNO_3 solution if density is 1.4 ~g / mL .

An element with mass number 81 contains 31.7 \% more neutrons as compared to protons. It symbol is

If molarity of Cu^ +2 ions is 3 × 10^ -4 express this in ppm

2 KHCO_3 …+CO_2+H_2 O find amount of gases formed (in lit). When amount of KHCO_3 is 33 gm .

Assertion : One mole of NaCl contains 6.023 × 10^ 23 formula units of sodium chloride. Reason : 58.5 ~g of NaCl also contains 6.023 × 10^ 23 formula units of NaCl .

The normality of 10 \% H_2 SO_4 solution having density 1.1 ~g / cc is

Mixture of two bivalent metals A and B having mass 2 ~g when dissolved in HCl at STP, 2.24 ~L H_2 is evolved. What is the mass of A present in mixture? (Atomic mass of A=15 u

A compound, containing only carbon, hydrogen and oxygen has a molecular weight of 44 . On complete oxidation, it is converted into a compound of molecular weight is 60 . The

In which case the number of molecules of water maximum?

A mixture of 2 . 3g formic acid and 4 . 5g oxalic acid is treated with concentrate H _ 2 SO _ 4 . The evolved gaseous mixture is passed through KOH pellets. What will be the

The normality of 10 \%(~W / V) of acetic acid is

The volume of water to be added to 100 cm^3 of 0.5 NH_2 SO_4 to get decinormal concentraction is

Combustion of glucose takes place according to the equation, C_6 H_ 12 O_6+6 O_2 6 CO_2+6 H_2 O Δ H=-72 k-cal The energy required for combustion of 1.6 g of glucose is

10 ~mL of liquid carbon disulphide (specific gravity 2.63) is burnt in oxygen. Find the volume of the resulting gases measured at STP.

Solid NaHCO_3 will be neutralised by 40.0 mL of 0.1 M H_2 SO_4 solution. What would be the weight of solid NaHCO_3 in gram?

11.2 L of gas at STP Weight 14 g . The gas would be

Suppose the elements X and Y combine to form two compounds X Y _ 2 and X _ 3 Y _ 2 . When 0 . 1mole of X Y _ 2 weighs 10g and 0 . 05mole of X _ 3 Y _ 2 weighs 9g , the atomic

How many significant figures are present in 0.0000135 ?

The amount of BaSO_4 precipitated on mixing BaCl_2(0.5 M) with H_2 SO_4(1 M) will correspond to

Assertion: One mole of NaCl contains 6.023 × 10^ 23 molecules of sodium chloride. Reason : 58.5 ~g of NaCl also contains 6.023 × 10^ 23 molecules of NaCl .

Which of the following is correctly arranged in order of increasing weight?

The number of water molecules is maximum in

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the

What is mole fraction of the solute in a 1.00 m aqueous solution?

If Avogadro number N _ A , is changed from 6.022 × 10 ^ 23 mo l ^ - 1 to 6.022 × 10 ^ 20 mo l ^ - 1 , this would change:

What is the mass of the precipitate formed when 50 mL of 16.9% solution of AgN O _ 3 is mixed with 50 mL of 5.8% NaCl solution? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5)

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?

The number of atoms in 52 ~g of He is

When 22.4 litres of H _ 2 (g) is mixed with 11.2 litres of C l _ 2 (g), each at STP, the moles of HCl(g) formed is equal to

1.0g of magnesium is burnt with 0.56g O _ 2 in a closed vessel. Which reaction is left in excess and how much? (At, wt. Mg = 24; O = 16 )

Strength of H_2 O_2 is 15.18 ~g ~L^ -1 , then it is equal to

In an experiment it is shown that 10 ml of 0.05 M solution of chloride required 10 ml of 0.1 M solution of AgNO_3 , which of the following will be the formula of the chloride ( X

0.1 mol HCl is equal to

Mole fraction of the solute in a 1.00 molal aqueous solution is

Which has the maximum number of molecules among the following?

100 ~cm^3 of a given sample of H_2 O_2 gives 1000 ~cm^3 of O_2 at S.T.P. The given sample is

When 25 ~g of Na_2 SO_4 is dissolved in 10^3 ~kg of solution, its concentration will be

Stomach acid, a dilute solution of HCl in water, can be neutralized by reaction with sodium hydrogen carbonate, NaHCO_ 3(a q) +HCl_ (a q) arrow NaCl_ (a q) +H_ 2 O_ (l) +CO_ 2(g)

Assertion : The molality of the solution does not change with change in tempe-rature. Reason : The molality is expressed in units of moles per 1000 ~g of solvent.

The number of atoms in 0.1 mole of a triatomic gas is (N_ A =6.02 × 10^ 23 ~mol^ -1 )

What is the molarity of H_2 SO_4 solution that has a density of 1.84 ~g / cc at 35^ ∘ C and contains 98 \% by weight?

To a 25 ~mL H_2 O_2 solution, excess of acidified solution of KI was added. The iodine liberated required 20 ~mL of 0.3 ~N Na_2 ~S_2 O_3 solution. The volume strength of H_2 O_2

10 ~g of hydrogen and 64 of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be

Assertion : When a concentrated solution is diluted by adding more water, molarity of the solution remains unchanged. Reason : Product of moles of a solute and volume is equal to

Percentage of Se (at. mass \(=78.4)\) in peroxidase anhydrase enzyme is \(0.5 \%\) by weight, then minimum molecular mass of peroxidase anhydrase enzyme is