Final answer:
Touching an electroscope with a positively charged glass rod will transfer some of the positive charge to the electroscope, causing the foils to separate further because like charges repel.
Step-by-step explanation:
If you remove the negative charge from the foils and then touch the electroscope with a positively charged glass rod, the foils of the electroscope will separate further. This is because when the positively charged glass rod touches the electroscope, it transfers some of its positive charge to the electroscope. As a result, both the rod and electroscope become positively charged. Since like charges repel, the leaves, which are now both positively charged, will repel each other even more, causing them to separate further. This effect can be observed in physics demonstrations and is a classic example of charging by contact as described in figure 18.11.