An element X has the following isotopic Composition ²⁰⁰X = 90%, ¹⁹⁹X = 8% and ²⁰²X = 2%. The Weighted average atomic mass of the element X is closet to _________.

(a)

201 u

(b)

202 u

(c)

199 u

(d)

200 u

The energies E₁and E₂ of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths ie \(\lambda \)₁ and\(\lambda \)₂ will be ___________

(a)

\(\frac { { \lambda }_{ 1 } }{ { \lambda }_{ 2 } } =1\)

(b)

\({ \lambda }_{ 1 }=2{ \lambda }_{ 2 }\)

(c)

\({ \lambda }_{ 1 }=\sqrt { 25\times 50{ \lambda }_{ 2 } } \)

(d)

\(2{ \lambda }_{ 1 }={ \lambda }_{ 2 }\)

The electronic configuration of the elements A and B are 1s², 2s ²,2p⁶,3s² and 1s², 2s²,2p⁵ respectively. The formula of the ionic compound that can be formed between these elements is ___________

(a)

AB

(b)

AB₂

(c)

A₂B

(d)

none of the above

Water gas is _____________

(a)

H₂O_(g)

(b)

CO + H₂O

(c)

CO + H₂

(d)

CO + N₂

Which of the following statements is in correct ?

(a)

Li⁺ has minimum degree of hydration among alkali metal cations

(b)

The oxidation state of K in KO₂ is +1

(c)

Sodium is used to make Na / Pb alloy

(d)

MgSO₄ is readily soluble in water

Select the molecule which has only one \(\pi\) bond.

(a)

CH₃– CH = CH – CH₃

(b)

CH₃– CH = CH – CHO

(c)

CH₃– CH = CH – COOH

(d)

All of these

For the following reactions
(A) CH₃CH₂CH₂Br + KOH → CH₃ - CH = CH₂ +KBr + H₂O
(B) (CH₃)₃CBr + KOH → (CH₃)₃ COH + KBr
(C) 
Which of the following statement is correct ?

(a)

(A) is elimination, (B) and (C) are substitution

(b)

(A) is substitution, (B) and (C) are elimination

(c)

(A) and (B) are elimination and (C) is addition reaction

(d)

(A) is elimination, B is substitution and (C) is addition reaction

The correct statement regarding the comparison of staggered and eclipsed conformations of ethane is (NEET)______________

(a)

the eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain

(b)

the staggered conformation of ethane is more stable than eclipsed conformation, because staggered conformation has no torsional strain

(c)

the staggered conformation of ethane is less stable than eclipsed conformation, because staggered conformation has torsional strain

(d)

the staggered conformation of ethane is less stable than eclipsed conformation, because staggered conformation has no torsional strain

The IUPAC name of  is ____________

(a)

2-Bromo pent – 3 – ene

(b)

4-Bromo pent – 2 – ene

(c)

2-Bromo pent – 4 – ene

(d)

4-Bromo pent – 1 – ene

The gaseous envelope around the earth is known as atmosphere. The region lying between an altitudes of 11 - 50 km is __________.

(a)

Troposphere

(b)

Mesosphere

(c)

Thermosphere

(d)

stratosphere