BLOOD
This plague is named after what you can see and not after what you can smell - although what you can smell is worse than what you can see!
In truth water turning into blood did not bother the Egyptian people very much, as it was common among ancient nations to drink blood. Imagine if turning on the water tap would cause Coca Cola to come out ... What made this a plague was the fact that the fish died, and as a result and the river became foul (7:21). That is why the Egyptians could no longer drink the water from the river. Therefore, the word ויבאש (the plague of the foul smelling waters) would have been a better word to describe the plague than Makkos Dam. The reason why the plague is not named בייאוש is due to the fact that the foul-smelling river was not visible to the eye. Thus, it is called DAM after the water’s turning into blood (Da'as Zekeinim).
Wine is the answer to my problem!
The reason why Pharaoh did not pay any attention to this plague (7:23) was due to the fact that he said that he was happy to be able to just drink wine from now on. It was only the general Egyptian populace that were suffering from the lack of proper drinking water (Sechel Tov).
FROGS
I would rather suffer than being embarrassed ....
Pharaoh asked Moshe to daven for the frogs to be removed from Mitzrayim. Moshe inquired when Pharaoh would like him to daven for them to be removed, and Pharaoh said 'tomorrow'. Moshe agreed and the next day he davened to HaShem to remove the frogs (8:4-6).
The question is, if Pharaoh is suffering from the plague of frogs, why did he not ask Moshe to daven to have them removed today? Why wait for tomorrow?
The answer is that Pharaoh was embarrassed to show that he was in critical distress due to the plague, and he therefore asked for Moshe to daven for their removal 'tomorrow' (Moshav Zekeinim).
Others say that Pharaoh had hopes that his sorcerers would find a way to remove the frogs today, so he told Moshe to only daven tomorrow (Tosfos Hashaem).
LICE
The wealthy don't have them and the poor anyways have them....
We don't find that Pharaoh asked Moshe to daven for the removal of the plague of Lice, as he had done by the previous plague of Frogs. The reason was that the lice only affected areas covered with dirt. Pharaoh and his ministers lived in houses covered with marble, and the floor was swept on a daily basis to prevent any dirt that would spread the lice. On the other hand, the poor people who lived in areas covered with dirt were anyways accustomed to dealing with lice on a regular basis (although, the plague of Lice was undoubtedly more severe than the usual bout of lice). Therefore, there was no compelling reason for Pharaoh to ask Moshe to daven for him to have the lice removed (Chizkuni).
WILD ANIMALS
How many times does the Torah mention Wild Animals?
None. The Torah only uses the word ערוב - multitude when describing this plague. There is no mention in the text that this plague was comprised of animals. This is why there is a machlokes In the Medrash (11:3) whether this plague was comprised of a crowd of wild animals (Rabbi Yehudah's opinion), or if It consisted of a swarm of wasps and mosquitoes (Rabbi Nechemyiah's opinion). [The Medrash brings a proof to Rabbi Yehudah's opinion from looking at how the plague ended. By the plague of the frogs died in the streets (8:9-10), and the earth reeked from the dead frogs. When it came to this plague, it says that they were completely removed from Mitzrayim (8:27). Why did they not die in the streets as the frogs did? According to Rabbi Yehudah's opinion it makes sense that the wild animals did not die in the streets, since otherwise the Egyptians could derive benefit from the skins. Whereas according to Rabbi Nechemiyah's opinion, the swarm of flying creatures should also have died in the streets like the frogs, as there is no use for their dead bodies. Therefore, the pesukim seem to indicate that we are dealing with wild animals.
What could save an Egyptian from the plague of the Wild Animals?
If the Egyptians would be in fortresses or towers, they would be saved (Bechor Shor). Likewise, if they would escape to Eretz Goshen (where the Jewish people resided) they would also be saved (Ramban, but see Ralbag that disagrees). Also, the shepherds managed to defend [themselves and] their animals in the fields from the Wild Animals, presumably using their sticks as their defense. This is why the Torah stresses that in the plague of Pestilence, even the animals in the field would suffer, as the shepherds would be powerless to come to their protection (Chizkuni to 9:3).
PESTILENCE
Can you prove that there were Egyptians who feared HaShem by the plague of Pestilence and did not fear HaShem by the plague of Hail?
By the plague of Hail, the Torah specified that only the people and animals that were outside would be destroyed by the Hail (9:19). The people that feared HaShem brought their slaves and animals into their houses to avoid them killed by the hail, whereas the people who did not fear HaShem left them outside (9:20-21). The question is, where did the Egyptians have animals from, if all their animals died in the plague of Pestilence? Rashi (9:10) explains that the plague of Pestilence also only applied to the animals who were outside but not to those inside the houses. Therefore, there were Egyptians who feared HaShem by the plague of Pestilence and brought their animals inside. They feared HaShem by this plague since it is a rather common occurrence, and so they took the warning seriously and brought their animals inside. But when it came to the plague of Hail, there were those who did not fear HaShem sufficiently, since it was a supernatural phenomenon, so they left their animals outside and they died (Riva).
According to the Ramban (9:3) the plague of Pestilence took effect on the animals inside the houses as well. The reason why there were still animals left in Mitzrayim after the plague of Pestilence is either because Pestilence did not kill all the animals but only the majority (Ibn Ezra) or around half (Bechor Shor). According to the Netziv, only the herds of animals died by Pestilence, but individual animals were not affected by this plague.
BOILS
Which three makkos were not life-threatening?
The Ramban says that the makkos of Lice, Boils, and Darkness did not come with a prior warning to Pharaoh about the impending plague about to transpire. The reason was that these three makkos were not life-threatening, and therefore they did not warrant a warning.
According to the Ralbag, it is entirely likely that Pharaoh was warned, even though no warning is recorded in the pesukim (see 8:12 and 9:8).
HAIL
Who thought that the makkah of Hail (11,1) counted as 4 makkos?
At the end of the plague of Hail, the Torah states that not only did Pharaoh harden his heart, but even his servants hardened their hearts (9:34). The reason that even the servants hardened their heart now was that they had been told that HaShem was going to bring 10 plagues upon Egypt. They mistakenly thought that the 7th plague counted as number 7-10 since it consisted of four elements: hail, fire, ear-splitting sounds (brought on from the storm-winds bringing the hail - Hakesav Vehakabalah, or from the smashing of the hail-stones on the ground - Netziv), and torrents of rain (9:33). Therefore, since in their minds the 10 plagues had already happened, they thought that they had nothing else to fear, and they therefore hardened their hearts (Tur).
GRASSHOPPERS
By which makkah did Pharaoh have flashbacks of little Moshe growing up in his palace?
At the height of the plague of Grasshoppers, Pharaoh calls Moshe and Aharon to come to him (10:16). Then he says "'please forgive me (singular, talking to only person) – ‘and please daven to HaShem for me’ (plural, referring to both Moshe and Aharon) (10:17). The Keli Yakar explains that the individual who was asked for forgiveness here is referring to Aharon and not Moshe. Pharaoh remembered Moshe growing up in his palace, and was well aware of his sterling character and humility. Pharaoh knew that Moshe immediately would forgive anyone causing him pain, so he did not even bother to ask him for forgiveness. Since Pharaoh did not know Aharon that well, he therefore had to ask him straight out if he would forgive him.
Which element from the plague of Grasshoppers was used in the plague of Darkness?
The plague of Darkness came about through a heavy cloud that descended upon the Egyptians. This mist was formed from the Western wind that carried the Grasshoppers away (10:19) (Abarbanel).
Others learn that the plague of Darkness was a plague that affected the eyes of the Egyptians, and thus temporarily blinded their eyesight (producing a feeling of Darkness) (Hakesav Vehakabbalah).
DARKNESS
Where do we find the practice of a chain-call?
Right after describing the plague of darkness, the Torah describes how Pharaoh calls for Moshe and tells him that he can leave with the entire Jewish people except for their animals (10:24). When did he call Moshe? Some say that this took place after the plague of Darkness, since during the plague of Darkness the Egyptians were not able to move (Bechor Shor).
Others say that Pharaoh summoned Moshe during the plague of Darkness as follows: Although the Egyptians were unable to move, they were able to talk. As such, Pharaoh called his servants who were stationed closest to him and asked them to pass on a message to call for Moshe. The servants spread that message to other Egyptians that were within their hearing range, and eventually this chain-call reached Moshe, and he appeared before Pharaoh (R' Chaim Potiel).
Pharaoh only called Moshe and not Aharon (10:24) as he was too embarrassed to humble himself and allow all the Jews to leave in front of both Moshe and Aharon.
When were Revenge and Curiosity two massive tests for the Jewish people?
The Chasam Sofer says that during the plague of Darkness and Makkas Bechoros the Jewish people faced two immense nisyonos (challenges) to see if they would comply with Moshe's instructions or not. Overcoming these two tests was the merit they needed in order to leave Mitzrayim. During the plague of Darkness, the Jews were told to go look and see where the Egyptians kept their money, so that they could ask them for it when they left. It was, however, tempting to take their possessions immediately while the oppressors were kept in Darkness and unable to move. The fact that they listened to instructions and did not take revenge was a tremendous source of merit.
Likewise, by Makkas Bechoros, the Jewish people were instructed not to leave their houses for the duration of the night. Imagine what it was like in a Jewish house when loud shrieks could be heard throughout the night. They felt extremely curious to see what was happening. Perhaps there was some kind of attack or war happening? Perhaps there was a massive fire or a flood? The restraint that they practiced by not going to find out what happened all around them, served as the second main merit with which they were able to leave Egypt.
MAKKAS BECHOROS
Who volunteered going into prison?
When Moshe warned Pharaoh about the impending Makkas Bechoros it says that all firstborn will die from the firstborn of Pharaoh who sits on his throne to the firstborn of the maidservant who is behind the millstone (11:5). However, later on when describing the unfolding of the plague we find from the firstborn of Pharaoh sitting on his throne to the firstborn of the captive who was in the dungeon (12:29). Why the change from the maidservant who is behind the millstone to the captive who was in the dungeon?
The Chizkuni offers two other approaches to reconcile the pesukim:
When the word spread that HaShem had warned that He would strike the firstborn, some reasoned that the captives in the dungeon are on a lower level than that of the maidservant. They mistakenly concluded that prisoners are excluded from Makkas Bechoros, and they placed themselves in the dungeon in order to be spared from the plague. However, the Torah testifies that even the firstborn who placed themselves in prison out of their own free will, also were subject to Makkas Bechoros.
Alternatively, when the non-Jewish slaves heard that the fate of their masters was equal to their fate, they had a level of satisfaction, knowing that they were not discriminated against due to their low status in Egypt. As a result of expressing this feeling, their masters were furious with them and placed them in the dungeon. Thus, the pasuk is describing where the non-Jewish slaves were at the time of Makkas Bechoros, namely in the dungeon.
Which Jewish people were allowed to leave their house at the night of Makkas Bechoros?
Although it clearly states ‘and as for you, you should not leave the entrance of the house until morning’ (12:22), that only applied to Jewish men. Jewish ladies and children were allowed to leave the house (and for this reason the pasuk uses the word - a man - to exclude ladies and children [Panim Yafos, see there that the ladies went and requested gold, silver, and clothing from the Egyptians during this night]).
Additionally, the simple meaning of the text states that after Makkas Bechoros Pharaoh summoned Moshe and Aharon to appear in front of him in his palace, which they did. This must mean that Moshe and Aharon went out of their houses on that night on HaShem's instructions (Ibn Ezra).