NEET Class 12

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NEET Chemistry Solved Question Paper 2004

Multiple Choice Questions

1.

Which of the following, is not a unit of pressure?

• Atmosphere

• Torr

• Pascal

• Newton

D.

Newton

Newton is not the unit of pressure. It is the unit of force. Atmosphere, torr and pascal (Pa) are the units of pressure.

1 atm = 1.01 x 105 Pa

1 torr = 133.3 Pa

2.

A golf-ball weigh 40.0 gm. If it is moving with a velocity of 20.0 ms-1, it's de-Broglie wavelength is

• 1.66 x 10-34 nm

• 8.28 x 10-32 nm

• 8.28 x 10-25 nm

• 1.66 x 10-24 nm

C.

8.28 x 10-25 nm

From de-Broglie equation,

3.

The enthalpies of all elements in their standard states are

• zero

• >0

• <0

• unity

A.

zero

The enthalphy of elements are zero in their standard state.

4.

Volume of CO2 obtained from complete decomposition of 20 g CaCO3 at STP is

• 2.24 litre

• 4.48 litre

• 20 litre

• 22.4 litre

B.

4.48 litre

$\stackrel{∆}{\to }$ CaO +

$\because$ 100 gm of CaCO3, on decomposition, gives 22.4 litre CO2 at STP

$\therefore$ 20 gm of CaCO3, on decomposition, will give

=  = 4.48 litre CO2 at STP.

5.

Which of the following order of ionisation energy is correct?

• B < Be < N < C

• Be > B > C > N

• B < Be < C < N

• Be < B < C < N

C.

B < Be < C < N

Ionisation energy generally increase in a period from left to right. But due to comparatively stabler configuration of Be (1s2, 2s2), it has more ionisation energy than Boron (1s2, 2s2, 2p1) Hence, the correct order is : B < Be < C < N.

6.

Which of the following acids is monobasic?

• H3PO3

• H3PO2

• H2SO3

• H3PO4

B.

H3PO2

H3PO2 or hypophosphorus acid is a monobasic acid. It gives only one type of salt e.g., NaH2PO2.

7.

Which is the shortest wavelength line in the Lyman series of the hydrogen spectrum? (R= 1.097 x 10-2 nm-1)

• 94.21 nm

• 91.16 nm

• 911.6 nm

• 933.6 nm

B.

91.16 nm

For Lyman series,

Hence, for $\mathrm{\lambda }$ to be smallest, n should be greatest (i.e. $\infty$)

91.16 nm is the shortest wavelength line in the Lyman series of the hydrogen spectrum.

8.

Which of the following ions, has smallest size?

• Ca2+

• Cl-

• S2-

• K+

A.

Ca2+

Ca2+, Cl-, S2- and K+ are isoelctronic species. In isoelectronic ions, size decrease with increasing nuclear charge. Hence, Ca2+ ion is the smallest among these.

9.

The significant figures in 1.0024, 1.240 and 0.0020 are respectively

• 5, 4, 2

• 3, 3, 1

• 5, 3, 4

• 5, 3, 2

A.

5, 4, 2

In 1.0024, all figures are significant.

In 1.240,the significant figures are four (zero tells about precision). Zero before a number are not significant, hence, 0.0020 has only two significant numbers (2 and 0 after 2).

10.

The shape of an orbital is determined by

• n

• l

• m

• s

B.

l

The azimuthal quantum number (l) determines the shape of an orbital. Fore.g.

l = 0 (spherical, s)

l = 1 ( dumb- bell, p) and so on.