A student investigates the rate of reaction between magnesium and hydrochloric acid. The reaction gives off hydrogen gas. The student wants to investigate how changing the concentration of the hydrochloric acid affects the rate of reaction. Look at her plan. First experiment I will put 0.5 g of magnesium ribbon into the flask. I will add 50 cm3 of hydrochloric acid. I will measure how fast the gas is given off. Second experiment I will put another 0.5 g of magnesium ribbon into the flask. I will add 100 cm3 of the same hydrochloric acid. I will measure how fast the gas is given off. Another student thinks that the plan will not work and he does not understand exactly what he has to do. Suggest how the plan for this investigation can be improved.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

the answer is 0.42 is that is an option. this question provides no info