Why the extra Lamed prefix, in the word "l'Chol Cheil Pharaoh"?
Rashi: The Torah often adds a 'Lamed.' 1
Rashi: Like we find in Shemos 27:3 and 27:19, and in Bamidbar 4:32.
Ramban: See above, 14:9.
Ramban: In which case, the word "l'Chol" is missing a 'Vav' ('ul'Chol'); and it is grammatically correct to add a 'Lamed' following the word "va'Yechasu Es ha'Rechev" - as we find in Yeshayah 11:9, and in Shemos 26:14 (See also R. Chavel's footnotes).
What is the Pasuk referring to when it adds, "l'Chol Cheil Pharaoh"?
Rashi: It refers to the chariots and the riders that are mentioned earlier in the Pasuk.
Ramban: Refer to 14:28:1:2 .
Seforno (to 15:9): It refers to the chariots and riders (private citizens) who followed the army to the battle-ground to share in the spoils.
Why does the Torah add the words, "Ad Echad"?
Chizkuni: It wants to stress that not even one soldier survived. 1
Da'as Zekenim and Hadar Zekenim: It means that one man did survive - Pharaoh. 2
Chizkuni: As the Pasuk writes in Tehilim, "Echad Meihem Lo Nosar - not one of them remained" (Tehilim 106:11).
Our verse does not tell us whether Pharaoh himself drowned in the sea! This point is discussed in the Midrash; according to Rabbi Yehudah, Pharaoh is included (among those mentioned here, who drowned in the sea). But Rabbi Nechemyah says, all the Egyptians drowned, with the exception of Pharaoh - as in the verse, "However, only for this have I kept you alive, in order to show you My power!" (9:16). Others (Acherim) say that ultimately, Pharaoh drowned as well. What is the reasoning behind each opinion?
Maharal (Gevuros Hashem Ch. 42, p. 159): a. Rabbi Yehudah explains that the reason our verse does not single out Pharaoh, is because the subject here is the water, which is inanimate. The water came down upon all the Egyptians equally, without singling out Pharaoh specifically - and so he drowned along with everyone else. 1 b. Rabbi Nechemyah - The purpose of Keri'as Yam Suf was so that the Mitzrim (represented by their king) would finally recognize Hashem's Great Name. Were Pharaoh to die, he could no longer recognize Hashem! 2 c. For the same reason, Acherim explain that at first, Pharaoh descended into the depths of the sea [alive], to fulfill the verse that he should recognize Hashem; and only then did Pharaoh drown.
Maharal: Other verses, in which the subject is how Hashem himself struck the Mitzrim, in fact do single out Pharaoh as a target. (The source the Mechilta cites is Tehilim 136:15; Maharal cites Shemos 15:4 .)
Maharal: R. Nechemyah will explain the verse "Not one of them was left" (Tehilim 106:11), to mean that not one of the common Egyptians who was supposed to die, remained alive.
QUESTIONS ON RASHI
Rashi writes: "Va'Yechasu ... l'Chol Cheil Pharaoh - It is Scriptural style to (at times) use an extra letter Lamed... merely to enhance the expression." Ramban asks - We may explain the Lamed as simply modifying the verb "va'Yechasu" - 'The [waters] covered the chariots... and [they covered] over all the soldiers of Pharaoh...?
Gur Aryeh: Ramban's example of such usage, is the Pasuk "'ka'Mayim la'Yam Mechasim' - 'as waters cover over the sea'" (Yeshayah 11:9). However, 'to cover over' (l'Chasos L'...) and 'to cover' (l'Chasos Es) mean two different things. Seeing as our verse starts with 'va'Yechasu Es ha'Rechev,' without a Lamed, Rashi prefers to keep the same translation throughout; and so he explains that the Lamed is extra for Scriptural style.