Explanation:
There are three states of matter:
1) Solid: In this state, the particles lie closer to each other. there is a strong intermolecular force of attraction between the particles.
2) Liquid: In this state, the particles are at a certain distance to each other. There is an intermediate intermolecular force of attraction between the particles.
3) Gas: In this state, the particles are farther from each other. There is weaker intermolecular force of attraction between the particles.
As the number of carbon atoms in a molecule increases, the number of particles increases and the particles will come closer to each other. Hence, the state of matter will shift towards the solid state.
Viscosity is defined as the tendency to resist the particles to flow. As, the number of carbon atoms increases, the Vander-Walls forces increases, the particles are closer to each other and Hence, the viscosity will increase.