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A sample of the hydrogen atoms is excited to the n=4 state. In the spectrum of the emitted radiation, the number of lines in the ultraviolet and visible regions is respectively:

(A) 1:3 (B) 2:1 (C) 2:3 (D) 3:1 The Correct Answer is (B) 2:1. Solution: Balmer series → Visible →... View Article

Assertion: Corrosion of iron is commonly known as rusting. Reason: Corrosion of iron occurs in the presence of moist air.

(A) Both assertion and reason are false. (B) Assertion is true, but the reason is false. (C) Both assertion and... View Article

Assertion: The order of bond angle of halides of boron is Bi3 > BBr3 > BCl3 > BF3. Reason: Greater is the size of surrounding atom larger will be the bond angle.

(A) Both assertion and reason are false. (B) Assertion is true, but the reason is false. (C) Both assertion and... View Article

The percentage composition of sodium phosphate as determined by analysis is 42.1% sodium, 18.9 % phosphorus and 39 % oxygen. What will be the empirical formula of the compound?

(A) NaPO4 (B) Na2PO4 (C) Na3PO4 (D) Na4PO4 The Correct Answer is (C) Na3PO4 Solution: The empirical formula is to... View Article

Which of the following phenomena occur when a small amount of acid is added to water?

(A) Dilution (B) Ionisation (C) Neutralisation (D) Both (A) and (B). The Correct Answer is (D) Both (A) and (B).... View Article

When the following aldohexose exists in its d-configuration, then the total number of stereoisomers in its pyranose form is:

(A) 8 (B) 16 (C) 24 (D) 32 The Correct Answer is (A) 8. Solution: The total number of stereoisomers... View Article

A 5% solution of cane sugar (mol. mass = 342) is isotonic with 1% solution of a substance X. The molecular mass of X is:

(A) 34.5 (B) 68.4 (C) 136.8 (D) 171.2 The Correct Answer is (B) 68.4 Solution: Given: 5% solution of cane... View Article

0.4g of an organic compound gave 0.188g of silver bromide by a halogen estimation method. The percentage of bromine in the compound is:(Atomic mass of Ag = 108, Br= 80)

(A) 20% (B) 39.8% (C) 40.0% (D) 48.0% The Correct Answer is (A) 20% Solution: Percentage of Br = \(\begin{array}{l}... View Article

An aqueous solution of 6.3 g oxalic acid dihydrate is made up to 250 mL. The volume of 0.1 N NaOH required to completely neutralize 10 mL of this solution is :

(A) 4 ml (B) 10 ml (C) 20 ml (D) 40 ml The Correct Answer is (D) 40 ml. Solution:... View Article

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?

(A) CHO (B) CH2O (C) CH3O (D) CH4O The Correct Answer is (C) CH3O Solution: The empirical formula is to... View Article

In Lassaigne’s test for the detection of halogens, the sodium fusion extract is first boiled with concentrated nitric acid. This is performed :

(A) To dissolve Ag2S (B) To dissolve AgCN (C) To remove silver halides (D) To decompose Na2S and NaCN The... View Article

For the redox reaction, MnO-4 + C2O2-4 + H+ → Mn2+ + CO2 + H2O. What will be the correct coefficients of the reactants for the balanced equation?

(A) MnO-4 = 2,C2O2-4 = 16, H+ = 5 (B) MnO-4 = 2,C2O2-4 = 5, H+ = 16 (C) MnO-4... View Article

An organic compound made of C, H and N contains 20% nitrogen. Its molecular weight will be:

(A) 65 (B) 70 (C) 100 (D) 140 The Correct Answer is (B) 70 Solution: The Atomic mass of nitrogen... View Article

Assertion: soft drinks and soda water bottles are sealed under high pressure. Reason: High pressure maintains the taste and texture of soft drinks.

(A) Assertion is true, but the reason is false. (B) Both assertion and reason are false. (C) Both assertion and... View Article

When two liquids of the same volume but of different densities, ρ1 and ρ2 are mixed together, then the density of the mixture is

(A) \(\begin{array}{l} \rho _{1} + \rho _{2} \end{array} \) (B)\(\begin{array}{l} 2\rho _{1} + 2\rho _{2} \end{array} \) (C)\(\begin{array}{l} \frac{\rho _{1}... View Article

A hydrocarbon C5H10 does not react with chlorine in dark but gives a single monochloro compound C5H9Cl in bright sunlight. Identify the hydrocarbon.

Solution: The molecular formula of hydrocarbons is C5H10, which satisfies the general formula CnH2n. This suggests that the hydrocarbon can... View Article

AB is a line segment and P is its mid-point. D and E are points on the same side of AB such that ∠BAD=∠ABE and ∠EPA=∠DPB. Show that (i) △DAP≅△EBP (ii) AD=DE

i) △DAP≅△EBP Given that, ∠EPA=∠DPB Now, ∠EPA+∠DPE=∠DPB+∠DPE Hence, ∠DPA=∠EPB Now, by using the triangles EBP and DAP, ∠EBP=∠DAP (given) Since... View Article

It is proposed to add to a square lawn with each side 58 m two circular ends the centre of each circle being the point of intersection of the diagonals of the square the area of the whole lawn is

Consider ABCD is a square lawn whose side is 58m. Also, AED and BFC are the two circular ends Therefore,... View Article

ABC is an isosceles triangle in which AB=AC.AD bisects exterior angle QAC and CD∥BA as shown in the figure. Show that (i) ∠DAC=∠BCA (ii) ABCD is a parallelogram

(i) ∠DAC=∠BCA Since, ABC is an isosceles triangle, Let, ∠ABC=∠BCA=y Also, given that ∠QAD=∠DAC = x (Let) By using the... View Article

If k is said to be a zero of a polynomial function P(X), if P(k) = ___.

According to the definition of zeroes of a polynomial, the real number “k” is said to be a zero of... View Article

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