0 10 20 burette (hydrochloric acid) meniscus NaOH + indicator white tile conical flask Fig. 1 This experiment is used to make sodium chloride from sodium hy...

This experiment is used to make sodium chloride from sodium hydroxide solution and hydrochloric acid. Fig. 1 shows a burette above a conical flask containing sodium hydroxide and an indicator. A student first carries out a rough titration. In later runs, the student adds acid slowly near the end-point, using the rough result as a guide. No excess acid or alkali can be removed by filtration because both reactants and the salt are soluble in water. The student repeats the accurate titration without indicator before evaporating the neutral solution.

(a) Give the name of the apparatus that delivers measured hydrochloric acid in Fig. 1. [1]
(b) Describe the colour change used to identify the end-point when phenolphthalein is used. [1]
(c) Use the reason why a second titration is done without indicator. [1]
(d) Draw a balanced symbol equation for sodium hydroxide reacting with hydrochloric acid. [2]

The diagram shows a gardener making calcium nitrate solution for a small hydroponic system. Dilute nitric acid is placed in a large beaker, and powdered calcium carbonate is tipped in slowly. The mixture fizzes at first. When excess solid remains, the gardener filters the mixture. This avoids putting carbonate particles into the irrigation pipes. The filtrate is a salt solution that can be concentrated carefully. The gardener notices that the reaction becomes less vigorous when the acid has all reacted.

(a) Give the name of the gas seen during the fizzing. [1]
(b) Describe a test for this gas. [2]
(c) Use Fig. 1 to give the salt made by this reaction. [1]
(d) Give one reason for adding calcium carbonate slowly. [1]