21.

Considering the state of hybridization of carbon atoms, find out the molecule among the following which is linear.

• CH₃ - C ≡ C - CH₃

• CH₂ = CH - CH₂ - C ≡ CH

• CH₃ - CH₂ - CH₂ - CH₃

• CH₃ - CH₂ - CH₂ - CH₃

Which of the following compounds has the lowest melting point? 

• CaBr₂

• CaI₂

• CaF₂

• CaF₂

The Lassaigne's extract is boiled with conc HNO₃ while testing for halogens. By doing so it

• helps in the precipitation of AgCl

• increases the solubility product of AgCl

• increases the concentration of NO₃^- ions

• increases the concentration of NO₃^- ions

Which one of the following is present as an active ingredient in bleaching powder for bleaching action?

• Ca(OCl)₂

• CaO₂Cl

• CaCl₂

• CaCl₂

Name the type of the structure of silicates in which one oxygen atom of [SiO₄]^4- is shared?

• Sheet silicate

• Pyrosilicate

• Three-dimensional silicate

• Three-dimensional silicate

The correct IUPAC name of the compound of 

• 3 - ethyl - 4 ethenyl heptane

• 3 - ethyl - 4 - propylhex- 5-ene

• 3-(1-ethyl propyl) hex - 1 ene

• 3-(1-ethyl propyl) hex - 1 ene

Which one of the following is most reactive towards electrophilic reagents?

Standard electrode potential of three metal X, Y and Z are -1.2 V, +0.5 V and -3.0 V respectively. The reducing power of these metals will be

• Y > X > Z

• Z> X> Y

• X > Y > Z

• X > Y > Z

The freezing point depression constant for water is -1 . 86^o C m^-1. If 5.00 g Na₂SO₄ is dissolved in 45.0 g H₂O, the freezing points is changed by -3.82^oC. Calculate the van't Hoff factor for Na₂SO₄.

• 2.63

• 3.11

• 0.381

• 0.381

For the four successive transition elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order?

(At. no. Cr = 24, Mn = 25, Fe = 26, Co = 27)

• Fe > Mn > Co> Cr 

• Co > Mn > Fe > Cr

• Cr > Mn > Co > Fe

• Cr > Mn > Co > Fe